I'm not too sure if it's gonna be as good as the hype suggest. Bethesda Softworks isn't making it, for one, and it doesn't have the same combat as the single-player games, the same goes for skill, progression, etc. In addition, open-world stuff is far from unique to TES Online. Beyond that, a lot of the stuff it's revealed is stuff that Guild Wars 2 revealed months ago.
So, I'm gonna play the pessimist and say it's not gonna live up to the hype, based on what I know. It's likely using TES as a lore point and world, and going from there to make a game similar to WoW/GW2. Which, by all means, isn't a bad thing. It's just not what a lot of people are expecting: Skyrim with other players.
Also, I'm not sure if it's been said whether or not it has a subscription fee.