Blockbuster
I've been using Blockbuster online for about two months and have never received a disk that was cracked, broken or otherwise unplayable. I did receive the wrong movie once but went online, filled out the little form and received the right movie about two days later.
It was really a toss-up regarding whether to go with Netflix or blockbuster. My wife really made the call because blockbuster gives you online coupons for in-store rentals, something that my wife liked. Netflix, of course, has no such feature.