EverQuest is better than World of Warcraft. Simply put..
Differences? hrm...A lot more classes..
EQ has Shaman, Shadow Knights, Enchanters, Mages, Necromancers, Beast Lords, Warriors, Clerics, Druids, Berserkers, Wizards, Bards, Monks, Paladins, Rangers, and Rogues.
like 5x more races..
Iksar, Ogres, Half Elves, Halflings, High Elves, Trolls, Humans, Erudite, Gnomes, Dark Elves and Barbarians just to name a couple.
72 Man raids instead of 40.
Better graphics in my opinion.
The largest difference in EQ and WoW would be the raids and the content. Progression in WoW is simple with the hardest thing standing in your way being the Onyxia Key Quest Chain, Which can be done in a matter of hours with a group of players.
Progression in EverQuest requires a raid force of usually 50+ people. Most times 72 in the newer content areas depending on your guild and it can take months to get flagged and keyed to into the highest zone(s) in the game.
Planes of Power was a prime example, Getting flagged straight through the Elementals and into the Plane of Time was a series of raid events across 10+ zones that all required a raid force of 72 in the beginning and took months to complete.
It's a lot more dynamic aswell, Encounters force you to pay more attention. A random player with get a single emote telling he/she to cast a certain spell type, If they don't do it they will litterally kill all 72 people within seconds.
EQ is just an all around better game, I played it for 6 years. I play WoW now but WoW will never get as good as EQ was in it's prime.