Netflix or Blockbuster?

I’ve been thinking about finally getting on the mail-in movie rental bandwagon, but I’m not sure which bandwagon is best.

Details about me: I have a Mac (boo for PC-only Netflix downloads), I live near a Blockbuster and I generally go for artsy films.

I know this has been asked elsewhere, but I’m curious to hear experiences from the collective. I’m especially interested in shipping times, scratched and lost discs, and other subjective info.