I'm using rails for my company but ruby is definitely not my preferred language. Blocks/Procs/Lambdas (why are there three almost identical constructs?) definitely don't compare to function application / currying. I'd much rather write in F# but I'm worried about all the nice to haves that come with the rails stack, like capistrano or the plugins to serve/upload your assets to S3. (e.g. ASP.NET has HAML but not sass)

I definitely foresee at some point switching to ASP.NET in a similar manner as twitter is moving over to the JVM / Scala, but rails still has a lot of legs in it for us.