Had one on my gpz and absolutely loved it. Will be ordering one shortly for my sprint. Intallation takes about 10 minutes and is pretty straight forward. Hardest part will be getting your old bar ends off. Manufacturers usually use the red loctite on them.
I've had one on my FJR and it worked great. I also put one on my sons "07" FJR and my daughter's "06" ZX6R. Work to relieve throttle cramp on long rides. They are easy to install and easy to use. If you get the heavy version you can't imagine how much additional bar damping you get. They also come with several different finishes.