PokerXFactor vs. CardRunners

[DiGiT 23]

I've been playing online and live for about 2 years now. I've had some success doing both, but feel like I want to take my online game to the next level. I play mid level cash games (1/2 or 2/5) and play a lot of MTT. My weakest part of my game has to be MTTs. I've been debating the value in joining PokerXFactor or CardRunners. I'm wondering if anyone has done so, if they can recommend one over the other, and how useful it was to their development. Thanks