My experiences have been with TigerDirect USA in Illinois.
In most cases, I've gotten the rebate, but it will take a long, long time. Don't hold your breath. If you get it within 2 months, count yourself lucky.
At least at TigerDirect USA, they claim that they have a "Rebate Guarantee." They even have a special website and instructions for that, telling you all these procedures you can follow to get a rebate that's late, to give you a warm fuzzy. I've never had to go to that extent, but I kind of doubt if that gets you anywhere.
I did have one manufacturer weasel out of giving me a rebate, because they claimed that I "forgot" to attach the original receipt. I did; they were just too lazy to go through all the stuff I sent them. Since it was only for $10, I didn't feel like arguing with them.