I think it's fine to go to Rails 3 at this point, so long as you're aware of the potential pain points (and as a older seasoned Rails dev, I'm sure you are). I

I think it's fine to go to Rails 3 at this point, so long as you're aware of the potential pain points (and as a older seasoned Rails dev, I'm sure you are). I would still probably shy away from Ruby 1.9.x unless you knew that all the tooling/libraries you would need were supported, or wanted to go through the upgrade process on other people's libraries/write your own. That said, if you're willing to do that, Ruby 1.9 is quite nice and a bit more performant as well.