I've been losing myself in the Elder Scrolls Online: Tamriel Unlimited Beta on the PS4 this weekend, and it is AMAZING. It really feels like Skyrim became an MMO... and got like 15 times larger.
Bethesda was REALLY smart with this Beta, though... they gave you enough "Crowns" to buy ALL the add-on DLCs (treasure maps, mounts, pets, etc) so you can check them out this weekend.
The skills system is kind of a mix between the standard TES version (all available from start, use them and they increase) and standard MMO (unlockable skill paths depending on class/race/actions)
Also, it's a no-subscription model, so it's just the original price and only DLCs are added cost. Dunno what the costs will be, though. They don't much impress me, so I can pass on them.