I run a computer repair business and deal with Tiger frequently. Yes, their rebates in the past were really spotty or would be rejected outright on first submission, making you resubmit (make copies of EVERYTHING!). Recently they've been much better, and I wouldn't hesitate to jump on this offer. Granted, you'll wait a little bit to get your money back, but free is free.
I would take the time to read ahead on the rebate info though to make sure you don't have to cut the UPC out from the game cover (like they do for video cards and other PC hardware). I've never seen a video game rebate on Tiger before, or maybe I just wasn't looking.