I've been doing Crossfit for 3 years (6 month break in the middle of 2011) and I have to say: Crossfit mixed with a disciplined Paleo diet makes incredibly quick changes. I have been back at Crossfit since October and have seen good gains. However, my biggest gains have been in the last 3-4 weeks on a strict Paleo diet. Just yesterday I PR'd by 3RM press, 1RM push press, 3RM back squat and made my old 1RM back squat look easy. While I still need to lose more body fat (love handles), I'm amazed that after 3 years, I still find Crossfit to be incredible.