I have only played for a few weeks so i dont have a great knowledge of server performance etc, but over the past week i have experienced strange lag and freeze ups. I had never noticed this before the last patch, but possibly this is just coincidence.
I checked the forums for any fixes and found the Pipeline = VFPF which in fact made my fps worse. I also found some info on router ports that could be opened which had helped some players. I opened these ports but have noticed no change. Sometimes i play and it seems nearly lagless, other times my character can not even take one step forward.
I really enjoy the game but there is really nothing more frustrating than not being able to move and i am not the only one with this problem.
I was trying to get a friend of mine to play and they told me to just forget it. They had already tried to play before and had nothing but lag and d/c issues and actually got mad at me for suggesting that maybe these problems had been fixed since they tried last.
It doesnt seem to matter which server i am on, i can log on and be moving around fine...all of sudden i cant move and i see all the players around me standing still. Sometimes a re-log fixes this, actually most times it seems to, but sometimes it doesnt...or it does for about 5mins until the next spike hits. I really hope you can work this issue out...i even noticed one of the lvl100 guys saying that lag had been crazy for him since the patch.
I see alot of potential in this game , very encouraging to see a developer speak one on one with the players...i have never seen that before.
Please dont take this post as a whine, i really want to see it fixed.

What ISP are you with? Do you do use P2P networks?

The reason I ask is that some ISPs have started to use traffic shaping. One of the ways they do this is monitor your usage and if they deem it too high then they throttle your connection speed to bring it down.

This means that web browsing and file transfers will take a bit longer. Which is annoying but not fatal. But for online games the lag it introduces can make the game unplayable.

Also some P2P clients are bandwidth hogs. The worst I have found is kservice. It will use all your bandwidth without asking you. This is the P2P client used by the BBC, C4 and Sky for their on demand services. So if you have installed any of them you need to disable kservice before running any online game.