Good For Smoothing Water
I like it for it's water smoothing capabilities. It's built well, screws on easily and the settings are clear and easy to distinguish. as others have mentioned you get some vignetting and dirty pics depending on how you have it set and what light is available. I'll keep it in the bag in case I need it for any special pics involving water smoothing. I should say I have a 10 stop fixed for another lens from them and it seemed to perform better, maybe because it wasn't variable??? I can't say for sure, just taking a guess as to why.