Stages 6800 arm because I live in abject poverty and can't afford 9k nor an SRM or something "good". I'll probably buy the power meter in August. Now, if I didn't recently incur $8k in medical bills which also required buying a car with an auto-trans, I would have picked-up a nicer carbon frame with 6800 or 9000. However, this bike in it's current form will do just fine, along with that poverty power meter. I finally got a chance to do a proper ride for the first time since the surgery and it was a religious experience.