When we started nearly two years ago, we had to quickly drop Windows and simultaneously learn Linux/bash, vim, Ruby, Rails, Apache, SVN plus million other things in a hostile and unknown land of old :-))) No, I have not heard of Merb back then, we compared RoR against PHP and went with Rails and so far it wasn't a bad ride. The key to NOT be disappointed is to do everything "Rails-way", i.e. treat DB as a dumb swamp where you keep your models. So far so good.