I finally got a chance to test these putters out this weekend (Thanks Steve!) and wow are they nice!
I have a 168 fire engine red X-link summit, a 173 minty-teal X-link firm VP, and a 170 x-link granite ridge.
My initial impressions of the VP were that it's too stable to be very useful. I thought it would be the best driving putter of the bunch, but it's such a pig that I can't throw it nearly as far as the others (I also live at 8000 feet, so they are all more stable to me than you lowland dwellers). Despite not being able to throw it very far, I think there is definitely a spot in my bag for it. I am a big fan of slow, freakishly overstable discs. I throw my Drone whenever possible for short chip shots, skip approaches, spikes, etc. I think the VP can play a role as an even slower disc of this kind, as well as a putter that is finally reliable in a 20+mph headwind.
The Ridge I'm finding very similar to my Wizards, and thus instantly workable. Just slightly overstable, they are very easy to putt with and throw. The marble X-link is nice, but I honestly think the other two solid colored Vibrams I have look sharper.
The Summit is the one that I'm REALLY started to like. It is strange because I normally prefer stable putters to understable ones. I took an instant liking to the summit because it looks and feels great and the low-profile mold feels super nice in my hand. But when I took it out throwing, I was amazed at how easy to throw this disc is. I found that I could very easily power up or down and still predict the amount of turn I was going to get. I was also throwing some ridiculous shots that I KNOW my Wizards aren't capable of. For example, playing a putter only round, I found myself jammed up behind a wall of 50ft pine trees. It was a situation where a thumber is almost your only option. Well I pulled out my Summit and jacked a nearly straight vertical shot on a stiff hyzer above the tree line...it stood up flat 50 feet high, panned right just slightly, glided about 80 feet and fell right next to the basket. I have NEVER seen a putter do anything like that. I was also able to absolutely crush this Summit. I threw it easily 375'. Way up in the air. I am still not comfortable enough with it to pull it out during a sanctioned round probably, but I am extremely excited about learning this disc a little better!
Vibram Chunk discs and granite Ridges available at wrightlife.com