Ok, first results after playing on the US server from Europe.
I avoided trying any form of PvP because I barely learned how to properly dodge, but I partecipated in numerous crowded PvE events without experiencing noticeable lag.
Then the server started lagging horribly but, apparently, that was an issue for everyone playing.
So far so good, tomorrow I'll try to get into some PvP matches and then we'll see if there's action in WvW.
Also, in game I'm Herla Wyrdson.