To me, the grips are a bit harder than stock grips, but they give you a much more positive "grip" feel. I think that they are a little larger in overall outside diameter as well, so they fit my hands better. I never really noticed much of an issue with vibrations from them, and I put a couple of 300 mile trips on the bike with them on.
I'm thinking that I may actually have to break down and put them on the 919 this weekend. The problem with installing them is that they don't just fit in place of your stock grips, they actually replace the throttle tube as well. That means that you have to disconnect and reconnect the cables to the carbs (on my Nighthawk) which was a bit of a pain. I'm sure that it's easier than I made it because I seem to take the long way to do everything.
2003 Honda 919 - flapper mod, Clear Alternatives Smoke Tailight w/ integral turn signals, Stebel Nautilus air horn, DIY fender eliminator, LED license plate bolts, LED front turn signals, no resistor or new flasher so I blink like crazy.