Howdy,
I'm a 8 handicap, been playing golf for about 25 years. I've used a variety of putters over the years, starting with a Bullseye and I'm now using a Bettinardi Kuchar, non-armlock. I generally use either a Superstroke Ultra Slim 1.0 or a Cameron Pistolero on the Bettinardi, so the Forward grip was quite a departure.
I installed the grip by blowing it on with an air compressor. This proved pretty difficult, partially because the fit is so tight and paritally because the grip is so large that it doesn't fit in the grip fitting I have (from Pure Grips). I solved that problem by cutting the fitting in half so I could get it around the grip.
The grip has a great soft, tacky feel with the micro ribs in the surface. I really like the triangular shape of the grip. It makes it easy to pick up and know where the face is pointing, something I never liked about the more circular SuperStrokes. The shape isn't consistent all the way down the grip, so you can't really grip down on it much. Your putter better fit for length before installing this grip.
Because of the large size of the grip, it requires very little grip pressure to hold. I have smaller hands (about the same as Jack Nicklaus, according to the printout in Golf My Way, just about the only thing we have in common) and grip feels good, maybe a touch too big? But time will tell.
One interesting thing with the size is that it forces my hands underneath the grip, kinda Corey Pavin style. I found this helped my alignment, as I have a tendency to get to on top of the putter and head left. The bigger grip brought me more "under" the putter, which helped.
The size also seems to take the hands out of the stroke entirely, which should be a good thing. I'm usually a slight arc style putter, but with the Forward on, I'm getting closer to a pure straight back and through motion. It'll be interesting to see how it affects things on the course.