I spent from December to March playing Elder Scrolls Online. I paid $30 for the privilege, and I feel that I got my money's worth out of the game.
The game itself is split into three segments: the primary play through, where you get all the side-quests and world-building quests, a second and third play through where you play through the storylines of the other factions, and a PVP storyline (I suppose, as I didn't do much PVP). Once you get to be a high-enough level, you can PVP, while the other area storylines weren't opened to your character until they completed the main storyline.
I appreciated how the game split the storylines into manageable chunks for their writing teams. One team wrote the main plot, which was the same everywhere you played. It didn't interact with the regional plots very much, instead focusing on the big story that drove all the regional stories. The guild stories spanned all regions as well, but they were optional (I assume). Each guild had its own crisis and opened up its own area in the end. Finally, each region had a crisis connected to the character of each region. The regional storylines were all unique, so the only way to experience them was to play through a second and third time. With this structure, each team was able to plot very independently, making an otherwise impossible situation workable.
Your character advanced levels, but in addition to advancing levels, they also collected experience in their skills. Even with allowing you to reallocated, you couldn't just become an expert in a skill immediately. You had to work it up. However, once you drop a skill, you'll maintain any experience that you have in it, so swapping back is easy, if expensive.
In terms of disk space, the game was a whopper, taking up 50 gb.
I played the game as an extended single-player game. I rarely teamed up with anyone, but I got through most things fine. Some things were frustrating, but often I only needed one other opportunistic player to team up with. Many dungeons were closed to me, but I don't feel that I missed much.
I found the crafting practical if uninspiring. I studied smith. The crafting gave me some advantage, but no more so than money would have. I could have gotten by on looted equipment. Crafting itself was mostly creating static recipes with mix and match bonuses.
All in all, the game entertained me well while I played it. I got halfway through the second set of quests when I hit my "I'm done with the game" apathy. I just didn't want to play it any more. My attention had simply wandered. That happens with me, which I why I only paid $30 for the game.
Overall, I rate the game as an enjoyable experience and I recommend it to my friends. It's a fun Elder Scrolls distraction and a fine addition to the Elder Scrolls line. Have fun. Play it. When you're done, move on.