I just bought some Tech Evo V2's over XT's.
After trying both here were my thoughts:
* Slightly lighter than V2s (not by much, about 120 grams with 180 rotors on both systems)
* Mineral Oil depending on how you look at it.... meaning to keep them from boiling they have to have: Icetech rotors (I don't like the idea of sandwiching aluminium between steel) and finned pads (these cost a FORTUNE).
* Plasticy lever that rattles when you move the reach in.
* Lack of spare parts, you break something and you'll be replacing an entire calliper.
* More powerful, better lever feel, better build quality, more servicable, you can run exotic brake fluid like Castrol SRF in them.
I went with the Hope V2's because I get through brake pads, I'd spend a small fortune on XT finned pads that I could spend on Castrol SRF or other bit's and pieces.
To finish think about this......
You'd almost be at XT weight with the V2's if you dumped the goodridge braided hose and went with standard hoses.