I just had a similar debate...it was a used Langster vs IRO vs all of the BD fixies.....

In the end I went with the Kilo TT Pro, $40 more than the regular seemed worth it (plus the colors are better) don't think you can go wrong with either.

Why..... in the end I just picked one and stuck with it, I debated and search for info for about a month and in the end people like the IRO people like the Kilo, and neither seemed to have much of a leg up on the other.

The langster was removed from my list as the used one locally was a 58 and I needed a 61...and it was the London version which is kinda flashy for my taste.

I can't comment on the bike yet as it is currently on the truck for delivery.