I use this for ND grads and polarised filters for landscapes on a G9. It gives it lots more fun-value, and some pictures I couldn't easily get otherwise - or couldn't get at all. I have also found that if I put a lens cap on I get more street cred on some occasions - looks like a grown-up camera.
Survived well fitted to camera in a ruck-sack, so tough enough. Fairly quick and easy to put on and take off. The only down-sides are (1) it blocks the optical view-finder (2) with some attachements you get vignetting at extreme wide angle.