I personally won twice on this website (waiting for my 2nd $200 gift card). I don't play too often, but its great to play around now because you get the card right before Christmas, helps a lot.
The downside is that you have to download and accept the agreements that go along with it, so pop ups can occur but doesn't happen too often for me. The other downside is that its hard to get the top score, some scores just seem impossible to beat. There are only a couple of games that I actually enjoy and will try to win because I know I have a chance.