I did this last September. Unless it has changed since then, they will rebate up to $200 in slot/video poker losses. The rebate is in the form of freeplay, with 50% of the rebate available that same day and the remaining 50% available after 30 days, but up to one year later, so it's really only a good deal if you plan on returning within a year. As I recall, you can't use the freeplay in any machine that has a progressive jackpot.
In my case, I lost $100 (the most that I wanted to risk) on video poker, used the $50 in freeplay right away on video poker, hit quad Aces for $200 and came out about $120 ahead, plus I still have $50 in freeplay waiting for me when I return this year (in April) so it worked out great for me.
Good luck!
