In all honesty, I have mixed feelings so far.
I'm far from an MMO veteran - I've only played WoW. Basically I got ESO because, when all is said and done, it is ESO.
There are some really good things - the story telling is excellent, the voice acting is good, and I like the way that you can 'build' your character. The graphics are OK - not brilliant, but decent enough. I actually haven't found any bugged quests or glitches yet, so thats not an issue for me at any rate.
The biggest problem for me is the immersion breaking caused by the other players. It's the little things really - you meet some dude who tells you that he has been 'waiting for a long time for a hero to come along' when its blindingly obvious that at least half a dozen other people are simultaneously having that exact same conversation with him. I realise there is probably no way around that, because its an MMO after all.
Perhaps I'm just not suited to MMOs? I dunno, I'll give it longer and see how I go.