To be clear, I’m interested in the topic, but I’m just not interested in having another pointless, reductio ad absurdum argument with you, which is why I did not quote you to solicit a response.

That's not what I meant by cross-threading. I'm talking about screwing the pedal into the crank on an angle such that the threads of the pedal and crank are mis-aligned. This can strip the threads on the crank or pedal.

How about an X/Y plot of precision vs. price? Stages, for all that they appear to be the most variable, also seem to be the cheapest.

It's pretty clear what you're interested in. I'm interested in not spreading misinformation. I wasn't really expecting that you'd engage in a good-faith manner. My comments were mostly for others, so they wouldn't be misinformed.

Yeah, that can happen, I suppose. never had it happen to my pedals, but with other bolts here and there.

As - I'm pretty sure - other said, power pedals for the win! It can be / will be a PITA if you swap them regularly however.

2 single sided PM (Stages or 4IIII for instance) could be another option at a similar price as well!

But cheapest doesn't mean best value. If the data the Stages provides aren't reliable and can't answer the user's questions (or worse raise even more questions), then the buyer didn't save some money over the more expensive option, but rather wasted the purchase price of the Stages.

Hence the X/Y plot of precision vs cost.

IMO, reviewers like DC Rainmaker and GPLama offer deeper insights and more sophisticated bases for purchase decision making than a crude X/Y plot of precision vs. cost would. I mean, there’s just a lot more info there, like about how the systems work, beyond just cost and “precision.”

Agreed. Though I'm pretty sure that it's accuracy rather than precision that you're after. Pretty much all of them read to a precision of 1 watt, AFAIK.

Also, many brands are sufficiently accurate such that accuracy stops being a deciding factor.

Repeatability (precision) may well be more important than accuracy.

Of course one might like to get up on one's Strava Stump to brag abut 1000W or 2000W, but the big thing is to know how one's current power compares to previous power outputs. Average power? Hill power? Sprint power? Intervals?

I considered upgrading my left side Stages Ultegra to two sided. But it appears that the right side Ultegra crankset design makes it difficult to get good accuracy. I decided it wasn't worth the extra cost.

My 4iiii left side failed a couple of months after the 3 year warranty ran out. This was last spring, during covid. It took months to get the answer that neither the retailer or 4iiii would do anything to help me out with a replacement. Not recommended.
My Stages left crank power meter is a lot better anyway. There's no 1-2 second high wattage glitches that I had to edit out, and the power seems more consistent to me. The Garmin zero offset works a lot better with the Stages too. And I get a "low battery" message on the Garmin.

Stats vs a training plan
I don't do a power based training plan. There, you can set goals for a big event day and see how you are progressing. Are the structured workouts improving fitness?
I use the power data for mainly two things:

1. pacing both shorter and longer duration efforts while riding.
I know what power I can maintain for 1 minute, 3 minutes, 5 minutes. It works great for pacing up the local 300 foot / 1 mile long climbs.
And what kind of steady state power I can do on the flats for longer periods.
Using watts is so much better for pacing than heart rate--which is slower to respond, or speed--which isn't easy on rolling terrain.

2. Stats after the ride, and seasonal trends.
I use the free, open source Golden Cheetah for post ride stats. And some stats on Strava Premium.

~~~

Strava Premium:
Calories burned. It's based on kilojoules from the power meter should be reasonably accurate. There's some variation person-to-person on calories burned vs calories of effective work.
on the web Strava: Analysis --> Power Curve. this picks out the best wattage during the ride, from 1 second to the length of the ride. And compares to the overall best efforts of the last 6 weeks or other selected time periods. It's interesting to see the best power for 1 minute, 5 min, an hour, etc.
25 watt power distribution. A bar chart with each bar a range of 25 watts. 1-25, 26-50, etc. Number of minutes and percentage of the total ride for each bar.

~~~

The free Golden Cheetah has these, and so much more. I really like it. It's possible to get started and just keep the defaults and only use a couple of the chart tabs, then make chart and settings changes later on.

CP chart. Critical Power, just like the Power Curve on Strava, but more control over the time periods for the max numbers. And it shows a selected interval from the ride on the chart too. I use this the most.
Calculated intervals: best 5 sec, 10 sec, 30 sec, etc efforts. Or make your own range selections. Or drag a section of the route map to make it an interval. Click one of the intervals from the list, and it shows where it happened on the map -- this often surprises me!
A "ride stack" graph. stacked up graphs of the ride. Can zoom or show a selected interval. Very useful.
Power, W'Bal, HR, Speed, Cadence, Altitude, Grade%. "W'Bal" is an estimate of my short term power reserves. It shows the available reserves dropping toward zero on longer, hard efforts, then building back up again as I ease up. Interesting and useful too.
Route map with selected intervals located on the route.
Power ranges bar chart, like Strava, but with adjustable intervals.
Power-Time Scatter. X axis is time in seconds, Y axis is watts. Each second of the ride shows as a dot! I usually have a 10-second rolling average for the dots to keep it a bit less scattered. It was amazing to me how much the power varies from second to second all during the ride. Even trying to hold an exact power number while watching the Garmin, there's a lot of variation.
And a bunch more charts. You can ignore the ones you don't use.

Seasonal or yearly trends:
RIders use this for training purposes to see if they are on track for the big events. I just like to see how I'm doing. And how it compares to previous years. Yes, I was just as slow in Feb-Mar of last year as I was this year, no worries.
PMC Performance Manager Chart. This uses a couple of different methods to track "stress" or "load. I can see that this year's spring rides compare well to previous years, and that I tend to level off during the summer, and slowly reduce toward the end of the fall season.
Summary page. Bests and averages of different metrics, historical changes, etc.
And many more charts that I rarely use.

I've been on internet discussion forums for almost 30 years now. RChung is a troll. Just ignore him or block him.

EDIT: After reading something around 10,000,000+ comments on discussion forums he's now the very first person I've ever put on my ignore list.

When there are solid numeric data, visual presentations of those data are a handy addition to the discussion.

My cat's name is Bear.

I tell him "if somebody does something you don't like, you can maul them." He has to understand it's part of being a bear.

He's getting agitated since we ran out of Temptations. I should probably fix that before I get mauled.

I don’t think such a thing would have any practical value to the OP, but they can speak for themself on the matter, and if they’re interested, you should go ahead and make the chart.

Not that you'll see this but I think it's probably good that you do this. You're happier and it doesn't matter to me because I get to make comments without your responses, so it's pretty much a win-win.

So, you've been reading over 900 posts per day, every day, for 30 years? At 30 seconds per post, that's over 7.5 hours per day reading forum posts. When do you ride?

With math skill like that, who needs hyperbole, eh?

Comments don't take 30 seconds to read, that's why. Your comment took about 3 seconds. My favorite political blog alone had 545 comments today. Another 500 or so trying to catch up on some gaming stuff on a gaming forum. 486 on my second favorite political blog. And them maybe 100 here. If it takes you 30 seconds to read your own comment, that's not my problem.

I was reading newspapers upside down when I was two (my mom would read the paper and I'd stare over the top of the paper from the other side). I'm a fast reader.

Why would I read my own comment?

Most comments people make are about as long as your comment (except on my gaming forum where it's often multi-paragraphs). Only a few sentences. And if you think it takes 30 seconds on average to read a comment then you're saying it takes about 30 seconds to read the comment you wrote, which is fairly typical of most comments.

Power meters are the best training/racing equipment you can buy, period. Buy used if you need. Its even more critical if you race triathlons.
Case in point. Did a 12 mile time trial last week and it was my fastest time from 3 I did in 2019. However my power was lower than all 3, which tells me conditions were much better for the last. Could be a little to do with being more aero, but no doubt my effort was over 20 watts less.

+1 on power meters in general

Having one totally changed the way I train and the way I ride, both measurably for the better.
I can pace myself much better on climbs. I learned that I started them way too hard.
I learned that I back off too much when cresting a hill or hitting a slight decline.
It takes the guesswork out of everything. I've read that "perceived exertion" is notoriously unreliable, but once having the power meter, I see that it's wildly true.
There are times I feel like I'm really mashing it, and I'll look at my power and say "WTF, that's all I'm putting out right now!?!?!" And the converse also happens
Plus, like the OP, I'm a data nerd and I love analyzing all my rides and interval session power data.

I only have experience w the Favero Assioma Duo, and I really like them so far (one year in)

[edit] while composing this post, I got an email from Favero that they just release the "Duo-Shi" which allows you to mount the Favero meter spindle into Shimano pedals ..
that's some weird internet timing, but a cool sounding product

https://cycling.favero.com/shop/assioma-duo-shi