It all comes down to what you want to do. If you pvp more than PVE, then horde in general have best que times for BGs. On realms where Horde out number allaince, alliance should have better que times. 2 years ago Horde pop was mostly older players 20 or older. that has now changed with new races. Not for the better for Horde. Check into population of server and bg grp. If you want PVE content then allaince may be a better pick. If you only wangt 5 man content then it does not matter. On pvp server ( depending on sever) 5 undead is always a good start.