I have Driven D3's, which are a "knock-off" of the Rizoma. I've probably ridden them 1000 to 1500 miles. I'm not the kind of person that puts a lot of emphasis on the feel of such things, but I can say the rubber portion is very soft. The aluminum sleeves are also a really nice touch, and I get very many compliments for them. The only downside is they seem to be wearing down noticably already.
Hope that helps some, it's not the Rizoma's but I'd waiger they are half the price and damn near the same thing.
I've never liked any type or kind of "billet or metal" grips. my bike is not a show bike so i try to keep it as comfortable and functional as possible. i've even ran those foam grips on one of my older bikes and they were great at sucking up vibrations AND water though!! so i've just stuck with the medium comp renthol's and keep copper BB's in the bars to soak up some of the vib's at freeway speeds. just my 2cents though. the rizoma's are nice though but to me i think anything metal will only conduct more vibrations but i could be wrong...wouldn't be the first time LOL!!