The PvP element is very very strong and well implemented in my opinion. It was made even more awesome by book 10 and its total PvP overhaul/upgrade. Now the PvP in LotRO is very diff from other mmos. It is only done in one zone called the Ettenmoors which is a massive instance. There is no PvP out side of this. Also you will not PvP with your main toon till you are 40 and even then most wait till 50. Untill that time you can immediatly PvP, however, by creating a Creep or evil creature (warg, spider, orc, etc) You begin at rank0 and can work up ranks which earn you many new talents/skills/upgrades for your Creep. Then you go to war against what ever Freeps (the PvE toons) are in the zone. There are tons of daily quests, hourly quests, Keeps to ransack and take over, and TONS of stuff to do in the PvP zone. There are quite a few solo quests in there too for both sides. Its pretty awesome with you have 40 freeps vs 60 creeps all trying to defend a main keep which has spike pits and traps and all kinds of chaos insuing.
Many ppl take there PvP rank very seriously on both sides. I played many many hours of PvP on my minstrel both solo, groups, and in raids. It is totally awesome and very exciting. I enjoyed playing a Creep for a little while but ultimatly I found that my Freep gave me more fun as I got to carry over my title and rewards to the outside world.
I would have highly recommended LotRO for both Pve and PvP well before book 9, 10 , and 11 hit which all gave MASSIVE content upgrades. New raids, New PvP, new Player housing.
The game just plain rocks, nuff said. The smooth run style is very eerie at first but once you play for a month it is totally natural and most ppl prefer it. I went back to WoW after 3 months in LotRO and realized I could nvr play WoW again. The run style + cartoon graphics + simplicity just could nvr cut it for me again after experiencing what LotRO offers.