Guild Wars 2 worked beautifully at launch. I had a couple of disconnects, but the game seemed to run perfectly even with 40 people escorting an NPC.
Right now, servers are down and have been since I woke up. Either the marketing people are there and bored or they pre-scheduled something, because I just received an e-mail encouraging me to join the headstart, buy Guild Wars 2, and start playing now! Bad timing, there.