I've got. Quite please with it taken some nice shots with it. Only reservation with losing filters is if you use the cokin slot type. I get reflections from the lens catching the light from behind the camera reflected on the inside of the filter. If I don't anticipate it (and becuase of the restricted viewfiner coverage I sometimes don't) then I need to crop the image by 10% or so to lose them. This is on a 400D, it got some reviews that stated fringing as a sligt concern, I haven't found that to be honest, it can be a little flat colour wise in some situations. Even at f5.6 I get decent dof from fore to back.
Other concern is that the focus scale isn't reliable at the infinity end (on my example at least) good build quality, only real regret is that it wont work on my EOS 3