I had them on my R6, people always commented on how bright they were, plus they have a couple of "modes" you can set them on, IMO, the best flushies out there, and I did my homework, way better than Gregs....trust me, youll be happy.
I had a budy that had them on his 929 and I wasnt a big fan, they definately were not as visible as the Protons ( because they stick out and the entire part gets lit up, you can see them very well) and the Protons are machined from a solid block of acrylic, they look really nice when mounted, they blend in well with the body work.
I have watsens. I had to wait a couple of months for them as they are made to order, not just pulled off a shelf and shipped. Well worth the wait IMO. Those s.o.b.'s are bright, even in the daytime. I'll be at Smarty Pants Wednesday evening if you wanna check them out.
Matt's are pretty bright too. They're both focused a little differently is all. Watsens focus the side and front; but you can see the glow from the back. Protons looked like they focused all around. Depends on what kind of finish you're looking for as well.
I had Protons on my R6 and loved them, I really liked how they fit right in the factory spot but were visible from any angle, and were bright enough in the daytime. Nicely machined too..