My suggestion is just pick one.
I'm using Rails and am quite pleased with overall simplicity and performance - both, of code and mine as a programmer.
Lately I've started looking at Smalltalk web framework Aida/Web. It has it's own pros and cons, but development is quicker (no restarts, can edit running code), it's lot easier on RAM then Rails and in 95% of time you don't need a database, just use image for persistence.