I've only been playing this mod for a week or so, but it is AWESOME. I really appreciate all the effort that went into this game, I get a tad giddy when playing as gondor :p
Aside from all the excellent textures/skins, I really like how the majority of gameplay dynamics were changed to fit the lore.
Glitches have been minimal (my favorite was when a few of my mounted gondorian generals started dressing like faramir), and the AI seems well scripted. Mordor sends stacks of troops at osgiliath and cair andros, harad makes occaisonal attempts at my coastal towns, Rohan and isengard usually do small skirmishes/massive seiges, everyone gangs on Ootmm....
I am VERY impressed with eriador/arnor. The way the reunification was handled is very nice (it felt a lot like unifying denmark and norway in the tuetonic campaign), and the prospect of sending some arnorians down south to pwn some orcs is pretty sweet.
The fellowship campaign had a few kinks (usually quests taking too long to trigger), but has been very enjoyable thusfar.