Of the three I've only ridden the Kaitai and it was nice, very nice. If you compare spec to spec the Roam may nudge the Kaitai but it's all about the other subtle things that you can only tell when taking them for a spin.

btw. I'm upgrading bikes this spring and the Roam and Kaitai were both in the running. My LBS's don't stock the Roam so without seeing it in person I've decided on the Trek Kaitai/Utopia/Montare line. I'll likely take the financially reckless route and go with the Montare

Good luck with your decision and keep us updated.