Over all, LotRO is a better game by far, but it lacks some of the "character" of AoC. Yeah, AoC is supposed to be grittier and all, but why can't the walking and running (and combat?) graphics of LotRO have more sway to them? I like watching my toons move in AoC, in LotRO they seem so stiff. Maybe it's the older, simpler (less bug-infested) design.
LotRO, even without it's expansions, has more depth. The deed system alone is worth it. I also like how there's no real need for changing levels (ie: mentoring or apprenticing) to group. The experience system allows upper levels to help lower levels with quests with no real disadvantage. It seems balanced to me.
And there's not one "uber" build, unless you interested in specific endgame areas like raiding or PVMP, which are worlds unto themselves. AoC seems locked into a niche, where certain builds just don't work well and PVP is mandatory if you want to be successful.
I see the fun in raids and PVP and am glad people enjoy those things, but I have no stomach or time for them. I have had too many bad experiences with the stuff to go out of my way to get good at them.
So back to my point, LotRO could improve a bit if it adopted some of the grit of AoC, but I am not about to give up my lifetime subscription.