Very few people play enough of more than one server to really know what more than one server is like. I play on Erica and love it. Some people like their server, some people don't like their server, some people love their server on some days and hate it on other days.
My theory is that the people who don't like their server wouldn't like other servers either since they have sour, negative personalities. Happy people are happy anywhere, unhappy ones unhappy everywhere.
Anyway, Erica has a middleing popluation, middling drama, but some very strong warring clans. You have to be good to thrive on Erica...if someone is successful on Erica they can be successful anywhere, but we see 'successful' people who come from other servers to Erica and then whimper.
There is a server rating poll in each of the Server Discussion Boards which you might find helpful.
Bartz is highest populated US.
Teon/Franz highest Euro.
Rest frankly dont matter very much honestly :/ Not enough play on any other server anymore...
Well, to be clear....Bartz has the highest NA collection of TOONS. (Toons = players + bots).
Or at least Bartz being biggest is what is usually said.
In C2 ALL servers had "heavy" status at log in. Doesn't mean a thing. Along came bot ban and "poof"--EVERY server (including Bartz) went to "light". Now Bartz and a couple others are getting heavier again--doesn't mean they have more PLAYERS....it just means bots are being re-established in greater numbers there, first.
After the ban--ALL servers had same residual population of PLAYERS. One would assume they still do.
Bartz beside being the heaviest NA server, also has the most pvp, entire server is waring 1 alliance and losing, but thats just cause that 1 alliance is so awesome at pvp + well organized.
Lionna, the first server i played on back in prelude, is for carebear larpers ...the people would act just generally weird, so i moved to bartz (the best server)