Personally, I don't think it will be that big of a deal to upgrade to Rails 3 from a 2.x app. They have done a good job of deprecating stuff, so Rails 3 should

Personally, I don't think it will be that big of a deal to upgrade to Rails 3 from a 2.x app. They have done a good job of deprecating stuff, so Rails 3 should naturally lead to a leaner Rails 3.1. While it might not be a standard app-maintenance upgrade, I think it's worth it if you have decent code with some tests. Also, not sure how it will compare to the 1.x => 2.x upgrade, but I was able to get a very complex application with horrible code and no tests upgraded from 1.x Rails to 2.x Rails. It only took me 3 or 4 days to get 90% of the app working. The rest was just stuff that I didn't find was broken. Since the app didn't have any integration tests, none of those features even got tested. I had to rely on traditional QA to find the errors, and this process took just under a month.