Oh man it is so much fun. I have to admit that when I first bought it a few months ago I played it for about 10 minutes then got frustrated and didn't touch it. This weekend I set the game up with 2x exp and 3x taming speed and a few other small tweaks and wow it became a totally different game. My daughter and I built a base, went on a expedition on a raft(and was attacked by a HUGE fish and was destroyed), tamed pterodactyls and flew to the mountains for metal(was attacked by a pack of raptors, won the battle but our pterodactyls left us for dead), tamed a male and female dinosaur and bred them, and so much more. Granted it is a hard game and it takes a beefy system but overall is a complete blast.
Next weekend we are going to each setup a base(creative mode type situation) then attack each other with cannons, ballistics, and dinosaurs. Quite epic.
I cannot comment on the multiplayer servers as we were playing all local. I think that is where most negative comments come from.