Netflix has worked well for me.
Only problem I have is that a lot of the reviews are people whining that their favorite show isn't on instant streaming and blaming NF. Problem is that Netflix doesn't set the rules: the distributors do. Likewise if there is a glitch in the program, NF can't do anything about it directly--it has to go back to the distributor and wait.
And of course, there's the fact that HBO has gotten tremendously greedy, pulled instant streaming for all of its programs from NF, and won't even sell them DVDs as a store: NF has to buy HBO DVDs from a 3rd party vendor at full retail price. And for some reason, people keep blaming NF for not having Dexter available on instant viewing.
Other than that, I usually get the next disk on a 3-day turnaround. Works pretty darn well.