For street riding

Comparably priced.
https://www.citygrounds.com/leader/le...bike-2013-3154
https://www.irocycle.com/markvprobuil...dwheelset.aspx

Leader 721:
Less comfortable aluminum frame
Sexy profile (imo)
Geometry?
Weight? (couldn't find this for complete bike)
Quality of components?

Mark V Pro:
More comfortable steel frame (possible heavier? [18.75lbs for 56cm is pretty good though])
Geometry?
Quality of components?

If you where starting out, which would you buy?

IRO is defunct.

Buying an IRO isn't going to happen. I'm pretty sure their entire operation was abducted by aliens.

So you are aware, that Leader complete isn't fixed gear. It has a Duomatic rear wheel, which means it's a two-speed bike with a coaster brake.

I had no clue IRO was donezo. How long has it been? They're website doesn't say anything about it.

What's another $500-600 steel bike with high quality frame?

I did not know that about the leader complete bike. Is it feasible to buy a 721 frameset, build it myself, and keep it under $600 without sacrificing too much quality for the other components?

Where are you located? In BC, Canada I see lots of IRO's pop up on used websites.

Seattle, WA. Any sites besides craigslist I should know about?

If you build a bike yourself, you'll be hard pressed to keep the cost under $1000 with quality parts. I suggest you look at the Wabi Classic for $750, and call it a day:

https://www.wabicycles.com/classic_bike_spec_11.html

The short answer? Nope.

What if I bumped that up to $750 to be comparable to the Wabi?

If you start with this, that leaves you with $350. By the time you're done buying a crankset, wheels, tires, tubes and pedals/clips/straps you'll be over budget (and still have an incomplete bike).

I'm building a leader 721, and mine is going to come out to about 600 with a crappy wheelset. Didn't skimp too hard on the other components but it's definitely a budget build. If I built it up with higher end parts I'd probably be sitting at about 1,000 dollars.
FWIW I'm really happy with my Raleigh Rush Hour, and you can score one of those for about 550 from your LBS

Kilo tt

Sure you don't mean the WT? That's been getting more mentions in recent weeks.

That Bikes Direct website is horrible. I'd never been there before because they don't ship to Oz and I feel absolutely no temptation to go there again, even if just for the experience ... if I want that sort of experience, I'll go play in the traffic

Well, I think I want to go as quality as possible. After touring a local bike shop, R and E Cycles, I think I'm gonna save up for a while and get a custom built bike from them.