I have an older IRO Rob Roy, which has been discontinued. I like it, but don't have any experience with any of their current models, which, I am sure, are fine.
IROs aren't anything special, but they are good solid reliable frames, and priced better than Surly's and a lot of the other brand names. The complete bikes are where IRO really shines...you get lots of custom options which minimizes the need to fine tune your ride or "upgrade" later on.