It all comes down to the code. Good code in a bad language is better than bad code in a great language. The nice thing about RoR is it kinda forces you to do a few 'best practices things' so even newbie developers tend to end up with 'ok' code. Of course, there are many PHP frameworks that also apply this sort of way of coding.
Also, note that there will be a learning curve (probably small, but you will notice it) when you first start learning rails. Like all new languages, you'll overcome this eventually.
There is really no reason to choose one or the other. You basically already know the answer. Whenever people ask me this question I say 'What do you think the pros/cons are for each language?' and then right after they list them I say 'ok, pick one'. This is really not a subject worth dwelling on with established languages/frameworks.