I have been riding U Di2 for about 6 weeks. At first I was luke warm ( my prior bike was an older 105 and before that friction shifter campy). So, after my luke warm initial experience, I have become more and more enthusiastic about electric shifting .... I shift alot to keep loading on my weak knees ... shift from the big to small ring and smaller to bigger cogs on the rear on grades easier than I could with my 105 shifters .... (other may be able to it just as fast with whatever gearing and shifters), so it is a worthy upgrade for me. I could go back to the 105, but the U Di2 experience is a worthy upgrade for me ....
YMMV

Pics!!!!

heresy.

Yes please post pics. My shop is contemplating bringing some some Raleigh Revenios that are going to be packing Ultegra Di2 but we are just not sure we can sell them.

Glad you like it. When I tested DA Di2 last year there was nothing like warm about it for me, I bought it immediately. Love that stuff!

I tested DA Di2 a while back and knew I had to have it one day, but it was just too expensive. Ui2 is 99% of DA Di2, but a heck of a lot cheaper. Even though mechanical can be set up perfectly, I would still take it over mechanical DA again.

Pictures of my Ui2:

Considering the other components on your bike and that it's a VWD frame, I am a little surprised that you consider Dura Ace Di2 too expensive.

I also think you're a tad generous with the Ultegra Di2 being 99% of Dura Ace. You could've said 80% or even 90% and I wouldn't have blinked, though.

It depends how you look at it. When I buy a component group I always consider the cost and weight when I make my decision. If the rest of my bike is light enough and nice enough to afford a few extra grams on the component group, I'll save several hundred dollars (or in this case thousands) by going with Ultegra over DA, Record over SR, etc. If you disregard the extra mass of Ultegra Di2, I'd say it's 100% of Dura Ace. It does the same thing and it does it just as well. Some like to say the Ultegra servo motors are "slower," but in reality they are just different, less expensive motors that work just as well. I think tomng made a good choice going with Ultegra. You also never know about a person's financial situation. He might not have been able to buy the S5 (it's a Team, not VWD btw) if he just had to have DA Di2 instead of Ultegra Di2.

My shop/employer is a Raleigh shop, and Raleigh+Shimano also sponsor my race team - so I've been riding a Raleigh Revenio Carbon 4.0 with Ui2 for a while now.
Compared to SRAM/Shimano (mechanical), the rear shifts aren't as good as SRAM, the front shifts are better. The bike is a different issue so I won't deal with it here - but strictly comparing groupset to groupset - Ui2 has it's advantages.

Overall:
If FD performance is a big deal to you, buy this stuff - it's like getting a winged unicorn carrying a magic wand and with a side of awesome.
If you are looking for faster than usual RD shifting, you won't find it here... buy SRAM or Campagnolo.


Price - not that much more costwise than other high-end groupsets... and make no mistake, this is a high-end groupset.
Mechanics - nice stuff, the auto-adjust bits are very nice. The charge lasts quite a while, but not as long as Di2 or Campy EPS... battery-charging-wise, if you can't be fussed to plug the battery in once a month, don't buy it and don't complain.

Shifting -
Front shifting - if you worry about front shifting, this will make all your problems go away. I did my best to make it mess up, uphill sprints with repeated FD shifts at high torque/low cadence, no problem. Repeated front shifts while also shifting the RD at high cadence on descents, no problem... I couldn't make it miss. This is the best reason to buy this groupset. It's stinking awesome.

Rear shifting - Shimano's isn't as fast as good as Campy & SRAM, still the case here. This isn't any slower at shifting than Shimano's regular drivetrains - but since I'm used to SRAM, I noticed it. The shift speed is fast enough to be just fine, I'd happily race it and never have cause to blame anything on it... but it isn't any faster than mechanical Shimano (It might be a fractions of a second slower - but I didn't notice a significant difference).
Since the negative points of reviews are what frequently stick out in people's minds - Again, it'll never be a problem unless your life/race/ego hinges on needing to drop 6 cogs in sub 2", in which case your gears aren't the real problem anyway. Without timing it, I'd say it could shift 6 gears in sub 3", but not sub 2". The two things I had to get used to while riding it were:
1: Timing: if you hit the shift buttons faster than it can shift, it'll forget your shift command. There's a slight shift-button-pushing-timing learning curve. For me, it took about 40' of riding it before I had it down and never had a problem with it again... just slow the button pushing down to the speed it is shifting at (which is still very fast) and it'll be fine.

2: Memory: On a cable system, shifting repeatedly will give out the appropriate amount of cable, so your RD will shift that much as quickly as it can, no matter how quickly you hit the buttons. On the Ui2 stuff, it 'forgets' the shifts that you pushed if it is faster than the RD's shift capacity. So, it'll shift as many times as the computer thinks you asked it to - see the previous point, just slow down the button pushing by a couple 1/10ths of a second and it'll not be a problem again. It took me about 40' to get this into my muscle memory, and it wasn't a problem again.

Still waiting for someone to come out with sequential shifts so you just press up or down and the computer decides which (or both) derailleur to shift. Yeah, I'm lazy like that.

I'm pretty sure Fairwheel created a sequential Di2 mod. Not really available as a ready product but totally doable for the tech savvy consumer.

I like Di2.

Ui2 is +/- the exact same thing with a lower price point...
I can't think of any reason other than weight-weenie-ism to buy Di2. Additionally, Ui2 is much more waterproof, and the cable harnesses are simpler & make more sense.

10k bike much....

As shown it's close in MSRP, but I should mention the wheels aren't mine and that the price out the door wasn't much more than other Ui2 equipped bikes. Considering that DA Di2 still has a street price of more than $3K here, and might be obsolete soon (different wiring, etc.) it made more sense to take the weight penalty and put it towards the frame. I was going to just go with mechanical Ultegra, but decided it was wiser fronting up the $1,000 now than inevitably upgrading in a few months.

I think if one rides DA Di2 and Ui2 back to back, then yes, you might notice a difference in how fast the RD shifts. So maybe it's not 99% in that respect. But for all intents and purposes, the shift is still fast enough that it's barely noticeable by itself, and definitely not going to cause one to lose a race. Weight wise, yes there's a penalty, but I live on pancake flat terrain, so weight is not a huge concern for me. If anything, the price difference between the DA Di2 and Ui2 could go towards upgrading other stuff.

Too heavy.

I've had DA Di2 on one bike for 7 months, and Ultegra Di2 on another for about a month. Functionally they are identical. The only difference I've noticed is that the servo on the FD on the Ultegra version makes a little bit different "zzzzt" sound when it shifts.

I have the wrong cable kit on the UDi2 bike. I need to get that fixed. The cables are too long and they wrap funny on the bike. On the DA bike the cables are held to the frame with heat shrink tape. Nice and clean (for external cabling anyway.) On the Ui2 bike the cables flap around and are only held on with zip ties. I get lots of "cable slap" noise. I'm going to remedy those things shortly.

Other than that unless you are seriously concerned about the weight difference, I don't see any reason to go with the DA version at this point.

When I buy my next bike it will have electric shifting.

With this, I totally agree.

If you live on pancake flat terrain, why would you need the best shifters money can buy. When I visit my folks in Indiana, I have 8 speed bike there and use maybe 4 gears. It's flat.

fify

Since when do people buy things based purely on necessity?

Dude, they go 'zzzzzt' when you push the button!

I buy a new bike every ten years and my current bike is three years old.