I started level my team at the EU launch. So far I've only been doing quests and played for about 17-18 hours done the underwater zone (can't spell) and am currently in Deepholm just dinged 83 on the team. The questing is not bad at all. Most quests have good respawn rates (although there are a few exceptions) and even though I'm on a PvP realm I haven't had much trouble with the other faction at all. There seems to be enough room for everyone to level.

I am not much of a fan of dungeon leveling hence why I picked the quest approach. Level 80 to 81 went a bit slower than I expected but 81-82 was very fast. 82-83 is a long run but very doable with the quests in Deepholm.