I've enjoyed it a lot, for following reasons:
The environments are beautiful, as others also have said. Especially the northeastern corner of Galen is dream-like in its wild beauty, the combination of lush vegetation and lava flows make it rather unique. I like Vastyr as a town, too.
The sets are interesting. Maybe not top notch for high-end PvE or PvP players (as some have complained), but not bad either. For instance, I could see myself using Back Alley Gourmand for characters built around dealing crit damage or Phoenix Moth Theurge for a jab-using Templar.
I like ToT, so a new deck is always welcome. I haven't tried it out yet, though.
Then, the story. It needed some polishing perhaps, but is solid in its core. The side quests were also enjoyable and fun. More detail below, to avoid unmarked spoilers:
The biggest flaw in the whole storyline was the handling of the Ascendant Order ideology. We never got to have even as much a conversation with a believer than with the other bad guy cultist in other storylines. Maybe the reason is that the stated goal of the organization (even if just a sham) would otherwise be too appealing to the players? After all, democracy is the current western ideal, unlike the medieval monarchy that is the basis of most Tamrielic societies. All we got as a discussion of the ideas was a quick dismissal by Lady Arabelle of it all as lies, and that was that. Braver writers would have really tackled the questions of noble-sounding revolutionary ideals turning into bloody fanaticism in the style of French revolution and of the possible justifications for power structures (maybe in Max Weberian vein). But then, I might be silly here. It is a rare video game and still more rare MMO that would attempt something that deep.
I feared that Lord Bacaro would prove to be the Ascendant Lord, and of course he was. Fine in itself, because who else it could have been? Count Mornard would have been almost the only other suitable candidate. My problem is how the reveal was handled. I can readily accept that a peace-loving philanthropist could concoct such a plot to remove war-waging monarchs from the scene to end the carnage, and the belief that he would be a better ruler. But the Druid King angle? There was no hint that I remember of Bacaro being descended from druids, and thus his whole motivation was undiscoverable until the big reveal. Otherwise, I liked the turn of events. The contrast between the soft-spoken Bacaro and Darth Vader-sounding Ascendant Lord was startling. And I couldn't help feeling a touch of sympathy for him because for all his ruthlesness and grandiosity, he also did have something of a point. In that, he resembles Magistrix Vox. The final battle in the mountain was suitably epic with all its trappings of lava and fire, and I enjoyed it tremendously. Heck, it was better than the scuffle with Molag Bal in the base game!
The other characters are very good. Frii was a bit boring at the start, but developed nicely along the events, so it was a bit sad to see them removed form the scene. All the good druids were interesting and if not always likable, at least relatable. I have to tip my hat to the writers for not shying away from killing many likable NPCs off. For instance, I had started to like Archdruid Rahval very much as he was a reasonable, nice man. So it came as a shock to see the villain cutting his throat. This also made me wonder who else could die, so this choice made events more supenseful. All the main cast was enjoyable to interact with (except for Za'ji, as I detest his voice). Even the minor NPCs were well done. E.g. the arch between Dame Fayda and Galphen was heartwarming, I was even a bit worried when for a while it seemed like Fayda had died. As another example, the Altmer woodworker with his awful jokes is hilarious.
In summary, I definitely got my money's worth. I'll definitely replay the whole High Isle-Galen storyline at some point.
