Shaders are alright, it makes the shadows and blood a lot better, but it smoothens out the otherwise rough force indicators on a joint (the ones that allow you to tell the difference between contract and extend quickly), making the game a bit harder to play. Although, they are great for videos and watching replays and the like.
About the framerate however, mine works in a wierd way. When I first load up the game with shaders on, I will get 30 or so fps, but sometimes after it has been open for a bit, I suddenly get a constant 60 fps, and it runs smooth as silk. Very strange.
Meh, voted third option