I don't have a role selection game in my collection, but I think I'm ready for one.As curtc said, Concordia is not really a role selection game, it's more like a trading game with deck building and network building.
I have, however, played Concordia and really enjoyed it. It's definitely meatier, which I like, but I'm not sure the theme will lure my group.
If you'd like to get the role selection game, think about Puerto Rico. Yes, it's not new, but there is still nothing moldy/dusty at it (and it won't be in 5 or 10 years).
But as you enjoyed Concordia, I'd also say: Go get it, it's a great and beautiful game!
A telediagnosis whether your group will like it or not is hard without knowing about the guys...
Are there very slow thinkers between them? (This may slow down Concordia and ruin one of its' biggest strengths, the quick and incredibly smooth gameplay.)
Are there any popular games your group did especially like or not like?
Does it need "Take that"-moments or big epic moves you'll remember to excite your buddies (there is not much aggressive interaction in Concordia and there won't be that one move that completely changes the game)?