From what I've heard, its really not a sublime job. You will be playing people's unfinished games. Like a teacher marking a rough-draft of an assignment or something. There will more than likely be problems with the game, and you have to play it for long enough to not only identify the problem, but I think you have to make reccommendations on how to improve it. Then they go away, make the improvements, and bring it back to you. You don't often just get to kick back and play the game, you have to keep an eye out for every little detail that is wrong with it. You'd probably spend aaaages doing that only, rather than neccessarily PLAYING the game.
It'd be more interesting to just play games that are already fixed up, when you get home from work.