Human can carry more loot.
Elf has more mana.
Choose based on that. If you use a lot of spells/specials, then go elf. Otherwise it doesn't really matter.
Most forget to take into consideration the reduced mana cost of being human. If you have a certain amount of skill points between weapon skills, poisoning, bushido, and ninja you get a reduced mana cost. This number is much easier to hit with human JoAT.
For PvP, mana is used for specials, and you can chain specials much more efficiently.
Now if you run a fencer/archer/bushido character or a ninja/nox/fencer Elf may be worth it because you'll have enough skill points as it is.
Also, in PvP there is definately something to be said for JoAT. Hiding, Spellweaving (attunement and gift of renewal), tracking, better stam/mana/hp regen. I prefer human in almost every scenario. My fencer/archer/bushy and my sampire are the only characters I would use as an elf.