I just started playing EQII last Wednesday. It's my first MMORPG(excluding the free ones I've played in the past like
www.odysseyclassic.com), but I did play EQ1 for two weeks in the past. So far I've been having a
BLAST with the game.
As far as performance goes, my system specs were originally...
P4 2.4GHz
512MB of memory
eVGA GeForce 6800GT 256MB(long live newegg!)
When I first played, the game ran smooth. When I got off the starter island and into my hometown, the game accessed my harddrive like crazy and would have 'hiccups' where it would freeze up for like 4 seconds every minute I when I moved around in the city. I figured this meant I didn't have enough memory so I put in a 1GB stick of memory the next day for a total of 1.5GB. After that, the game was running smooth as silk. Don't be fooled by the minimum system reqs on the box, you definitely need 1GB of memory or more. I set the setting to 1028 x 1024 resolution with 2x antialiasing, the highest quality textures, shadows enabled, draw distance pushed all the way up, etc. Smooth as butter.
As for the actual game goes, I'm really loving it so far. I played two weeks of EQ1 and it left me with a bad taste in my mouth. EQ2 killed off everything I hated about EQ1.
-EQ2's music and graphics kills EQ1's 20 times over. ESPECIALLY the music.
-I hated combat in EQ1. It dull and wasn't very fun to watch. In EQ2, you have the option of watching combat from a third person view which is a lot more entertaining because it has that whole "Bioware"(NWN, KotoR) thing going on where you see your character actually dodging, parrying, and blocking hits instead of just seeing the message "You parry an attack!"
-You can customize your character with a LOT of depth: scalable body size, eye color, eye shape, jaw size, nose size, ear size, etc. Not as deep as you can in The Sims 2, but it's still a lot of options.
-So far the servers don't seem to be too heavily populated(everyone playing WoW?

). This might be a good or a bad thing depending on how you looke at it..
-There's player-housing options where you can decorate your pad ala Animal Crossing. Then you can give access to your house to your friends so they can visit your home even if you're not around to let them in.
-In general, combat seems more rewarding overall. Sometimes when you kill a baddie, a treasure chest will show up and sometimes it doesn't, but when one does, there's usually something interesting inside. Though, when I grouped up with two other people last night and we were killing animated skeleton warriors at a graveyard, the chest that dropped was trapped and I we got hit for about 200+ in damage.

-Any race can become any class unlike that old AD&D formula games were following of Elves not being able to become paladins. But alignment restrictions apply(e.g. no evil paladins). I have an evil Dark Elf crusader currently. When he gets to level 15, I'm gonna start the city betrayal quest, see if I can turn him good, and make him a Paladin.
-Usually with the MMORPGs, you kill baddies and then you have a period of "downtime" where you have to wait for your stats to regenerate; usually several minutes. With EQ2 they cut down on this by having it so that all of your vitals regenerate instantly every time you earn a certain percentage of exp toward your overall level. So if you time it just right, you can start a fight against several enemies where you would naturally get your ass-kicked, but not have to worry because if you kill one enemy in the group you'll get the exp and instantly heal, making killing the remaining enemies easy.
Probably what I don't like about EQ2 so far is there's no multiclassing, though once again this might be a good or bad thing depending on the person. On the MUD I play, just because I'm and Elf, I suck at Paladin skills even as a single class pally, yet a multiclass dwarf pally/mage is still at better at paladin skills than I ever will be because dwarves are considered 'natural' paladins. With those type of restrictions, I am cry.
I think the only reason I chose EQ2 over WoW is probably because of the amount of customization you can do to create your character's appearance instead of just 'choosing' a model. In the end, you probably can't go wrong with which ever game you choose because devs have learned a lot about how to make a good MMORPG these days by looking at the good/bad of EQ1 as an example.