Yeah unfortunately the servers haven't been great, i've been able to play all day but only managed to get to level 18. There was really shitty lag which started at around 10am, then the servers went down for an hour, still lag when they came back up. Then they went down again about an hour later for a 35 minute scheduled maintenance, which ended up taking 1.5 hours, but the lag was gone and it was running really smoothly for about 1.5 hours. Then they took the servers down for "15 minute emergency restart" which lasted almost an hour, and when they came back up they were laggy again and have been ever since.
Obviously I've been logging in straight away after the maintenance so I never had to sit through any log-in issues or character creation issues, but honestly, even when you're in, apart from that 1.5 hour period in the middle of the day, it's been a pretty shitty experience. All I can reccommend really is pretend the launch is tomorrow/Thursday, and try then unless you're really eagar to play like I am.
P.S - By laggy, I mean literally freezing and running on the spot for 10-20 seconds every single time you kill an enemy (The lag seemed to be linked direcly to objects being spawned on the ground, such as loot), which was borderline unplayable, especially when you'd kill 1 out of a pack of mobs, and then freeze for 20 seconds, and come back to the rest of the pack having killed you while you were lagging out.