Horde/Alliance?

Hi I have just a quick question. I'm not sure if this can really be answered but I am curious about which WoTLK server to play and faction.
Is there any difference between the factions on the WoTLK servers PvP wise? Like are there more PvP guilds and PvP activity on any of the factions?

I know it's an odd question and maybe it cannot be answered to 100% but I'm just curious.

Not sure about WOTLK realms but I would suggest checking out so you can see which community is more active during the time you play. Also, looking at the guild recruitment section might give you an idea of the activity levels.