Just my twopence-worth, having participated in both beta tests:
EQII: I initially enjoyed my time there, lots to do, plenty quests, nice progression rate. Towards the time of retail, having reached the dizzy heights of 18 Brawler/19 Outfitter, I was less sure that it was the game for me.
Being a casual player, I have limited time and don't wish to spend it LFG, which happens more and more as you rise in levels. Solo content was cut back (all dungeon content became group-only), cutting back on my enjoyment of the game. There were also stability problems with the servers, which (judging from my guild board) has carried over on to the Runnyeye server at least after release.
The game was gorgeous, with plenty character customisation and a gritty, real-world feel to it. I had few problems with the graphics, but had them optimised for performance. Still looked very nice though. Also, all the NPCs spoke! And the voice acting was pretty good - only a few howlers I heard (and bugged!). Mainly relating to US actors trying to do Scottish/Welsh pronunciation
Having come from EQI, however, I found it a bit too similar - and the mass of changes just prior to release knocked my confidence a bit as to how the game was going to progress. I planned to wait until March next year and give it a go for the free month that comes with purchase.
WoW I was then lucky enough to get into the WoW final beta test. At first I thought "I've fallen into an Asterix cartoon!" as the graphics were much more stylized. However, as I continued to play, the graphics seemed to fit more and more - I actually felt like I was in a fantasy world, and the graphics helped that.
The game is just as well paced in the early levels as EQII is - quests abound, the only difference being that the quest-givers are easier to spot. In WoW the have a big orange ! over their heads - in EQII you pretty much had to hail all the NPCs to see which ones had quests to give you. There seems to be a bigger variety in the types of starting area also, with the frozen mountains of the Dwarven starting area contrasting with the open plains of the Tauren. I'm sure EQII will have as much variety as content is added though.
The game is much more accessible as a casual player - most mobs can be soloed, some grouping necessary to complete some quests - but a lot less than EQII.
There is not as much depth to the crafting in WoW, but it is therefore also much easier to get into. Once again, all the NPCs speak to you, with the voice acting on a par with EQII. There are some nice touches - I tried to loot a corpse that showed it had loot on it and had been killed by a group member - A voice then piped up (in best 'Groundskeeper Willie' accent, being a dwarf) "That would be stealing!"
I really wanted to give EQII a try, but found it too much like EQI - grinding exp, spending ages LFG to get a quest completed, or to explore an area. I still think it's a good game, but WoW suits my available playing time so much better, I think that it will be my game of choice this winter.
This is all my subjective opinion, so don't be too harsh! EQII might well be the game for you - it just wasn't the one for me.