If you have played a caster, you will notice that sometimes your cast bar will go to 100% but your spell will not cast (especially if you are getting hit by a mob/player). Spell push back is a good mechanic, but is fairly useless when your cast bar does not work properly - all you can do is guess when your spell will actually go off. This happens to other classes as well, such as scouts not doing the correct damage until their second shot (according to a friend).
Aside from classes, there also seems to be a glitch with players' hp bars. Sometimes you will get hit for damage that won't show on your screen and won't update your hp bar. The only change is in the numbers on your bar, but honestly, who really pays attention to that all the time? In most of these situations, you won't even be aware of what is happening until you are dead.
Unfortunately this also affects global cool down and cast cancellations. Its lag that doesn't really exist, but is probably caused by information delay from the game client to the server. For me, sometimes it feels like the ghost lag gives me an extra 200-400ms of ping.
I don't believe its the servers, but rather how the client actually deals with sending information packets. Hopefully it will get fixed in a future patch, but we'll have to wait and see.
As for my character progress, I have arrived in Eljune at level 28! This place looks rather cold and gloomy though. :(
As of this entry, I'm only 80% away from dinging 40. I'm not too fond of Dragon Ring, after dodging 2 geared 40s with warbanners pat...