> because you can easily find a guy who worked with Rails framework and knows it inside out
That's only relevent when you are hiring someone to deal with the monstrosity of a rails app that you ended up with because the abstractions didn't quite work for the problem you were trying to solve.
I've found it very easy to use some Rails best practices in a Sinatra app and not have to deal with all the routing/controller cruft in Rails, while still getting sensible filesystem conventions.
That's only relevent when you are hiring someone to deal with the monstrosity of a rails app that you ended up with because the abstractions didn't quite work for the problem you were trying to solve.
I've found it very easy to use some Rails best practices in a Sinatra app and not have to deal with all the routing/controller cruft in Rails, while still getting sensible filesystem conventions.