I have a year old 318 U-turn. Left leg seal blew inside warranty and rebound cartridge died. Sent it back under warranty via LBS, asked to have heavier spring set installed and has been good since. If you are a heavier guy 200lbs + you should get the heavier springs.
Otherwise I love the plushness, stiffness, and the M-axle is great. For the price I recommend it. I guess longterm is yet to be determined and I have always run Marz previously so will see.