In my mind, Caine kinda started the whole V2 craze or recent. (not that I mind seeing more and more wonderful V2s around here).
IMO, Caine's V2 is really the epitome of V2s as so many of these sabers are based off of Caine's original design, especially the use of the touch plate activation (and soon to come, clash flash!)
And LDM, about the subtle differences. I was thinking earlier about what would happen if we placed all the V2s of this style on a table next to each other and we took some random people and ask them the differences they would see in the sabers (probably no differences). But if we just took a look at the V2s, we'd instantly be able to tell which one belongs to us.
I like how even same sabers of a specific design (most of these are based of of Caine's) are still so very different.