For a difference of $50, the faster CPU and larger drive is worth it, if for no other reason than all the trouble you'd have to go through to try to upgrade it later assuming the CPU in those is replaceable and not soldered to the board.

I don't know about the battery life, but I think there is an aftermarket battery available for those with a longer lifespan than the ones that Apple originally shipped them with. I can't remember where I saw it, but it was one of the more popular used Mac dealers so it shouldn't be too hard to find with Google.