I made a character to check it out logged on 3 different times on the sith fleet, 2 of the 3 times tofn had more on line, and both times by a big difference.
so i don't know about the other server having more not that it really matters as one is a pvp and one is teddy bear server, so its what suits i guess.
Oh you are talking about PvP servers? No, not interested.
I love the "risk" involved where you can be killed by other people, it is what made UO so amazing in those early days.
However SWTOR just had groups of Lvl50 and then 55 marching around the lower level planets slaughtering everyone.
There is PvP and then there is that - the reason I will never play on a dedicated PvP server with this game.