This server is so big that it makes no difference, neither side is better. Yesterday I haven't lost a single Pub PvP match, today I have lost all of them. HM FP's usually go worse on Imp for me but that's just bad luck I have had terrible and awesome runs on both factions.
Decide what class you want to play and then ask yourself what animations you want to see
Rocks/Bubbles - Lightning
Electricity/Rounds - Flames/Rockets
Blue saber fx - Red saber fx