I have been playing MMORPGs for more than 14 years, and i am seriously enjoying ESO. Questing is really fun and immersive. There are quests with no markers but just hints (example: a letter tells you the steps you should follow to find a treasure); most of the ones i completed so far are interesting, and quality wise better than your average MMO (kill x amount of y).
There are a lot of incentives in exploring the world, you can find quests, treasure chests with really good items, books to read that give you skill points in weapons and armor, skyshards, and more. Crafting is also very interesting.
Cant wait to jump into the PvP campaign, as an ex DAOC player i am intrigued.