I'll try to provide as much information as I can, feel free to ask questions.
THE PROBLEM:
Playing on the EU server, I have experienced minor connection stutters and overall lag.
During the Beta Weekend, I have played on the US server, and although my latency was higher I did not experience any kind of noticeable lag. This is what strikes me the most:
I have experienced more lag on the current build while having a lower latency, than I had on a previous build with a latency twice as high.
THE SYMPTOMS:
Other player's ships and aircraft squadrons teleporting small distances at random intervals. No noticeable lag with my own ship; e.g. animation of cannons is fine. Does affect playability as it is a slight annoyance during combat (e.g. missing shots because the enemy's position was incorrect due to lag).
FPS stable at 58-74, latency always around 30-40 ms.
On the US server, I had a latency of 70-80 ms.