I have the single track UV version of this cube and it is my new main over the Vin 4x4 (normal). The cube is quite fast and light in turning with a smooth but slightly "sandy" feeling (I don't mean sandy in any negative way). Corner cutting is pretty good and the cube is pretty stable. I have it on fairly normal tensions and it does not pop or lockup. The cube is also smaller than the vin and I personally like it, I wouldn't want it to be any smaller though.
Overall I prefer this over the vin and I'd recommend it to everyone. I do wish they included a blank white center cap so I could use it for 4bld.
I have tried the double and triple track versions a little bit, I didn't like the double I felt as much but I did prefer the triple. It was more stable than the single but otherwise preformed similarly. So if you are fine spending the extra money go for it. If not the single one, UV or not, is still really good.