A buddy of mine said he was waiting for this for a long time to be released (no idea why, I never heard of it until this thread) and he already requested a refund on Steam.
He claims the stuttering issue isn't a small issue like some claim it is. He says it can get bad enough you can screw up your attacks completely or it'll simply get you killed. He also said there's a lot of collision issues with the geometry and several times he just fell out of the map. There were a lot of other things in his rant about the game, but since these are his words and I never played it, I'll just leave it at these two issues (which seemed to be the main aspects of his refund).
And this is exactly why I never pay full price for a game. I'm sure all of these issues will be eventually worked out, but this is why a lot of games flounder. The first impressions are the lasting ones and if you get a Dead Island first impression, you're going to lose a massive amount of potential fans very quick.