The good;
The combat is fantastic. Fifty+ abilities, but you can only chose 5 and an ultimate. So the customization options are incredible. Plus the way it works, you have traditional elder scrolls light and heavy attacks, with blocking abilities.
When fighting, it isn't just mashing buttons, or getting off some preplanned combo. It's actually a complicated fight. Like against a melee enemy, I know that I can block or dodge his things, I can look at the environment around me, if there are any nearby rocky I can try to jump onto one of those to hit him from above etc. There are about 10 different abilities NPC enemies use. And they all have gives for when they're about to use them. Like they might start channeling a fireball in their hand, or raise their sword up slowly. Either way though, the game offers you options to dodge or counter all of them. The way that most ESO fights are different makes it a top tier MMO combat experience.
The leveling is also top notch. At least at the beginning. You go 1-50, you get a skill point an an attribute every level. But it gets better. Cause with those skill points, there are 50+ skills that you can level individually. Each skill has levels 1-4, but then after level 4 you can morph it to one of two unique other skills. You can also level some 30+ passives, to gain more armor, or crit or whatever you want.
There is also, about 15-20 skill lines. Which you also level independently. Like each class has 3 skill lines, with 5 active skills, 5 passives, and an ultimate. then there are 7 different weapon skill lines, and 3 guild and just, there are a lot of skill lines. Leveling skill lines helps make those skills more powerful but also unlocks the ability to unlock a skill. Like if I have 4 skill points and level 20 bow, I can unlock the first four abilities of Bow. But the fifth one can't be unlocked until level 38 so I couldn't grab that one.
While their are only 4 classes in the game, the classes don't matter that much. I am a nightblade, which is the assassin role, but I can play tank or healer when I want. There is only a slight disadvantage to being a nightblade rather then an actual Dragon knight.
The Questing is possibly the best in the MMO genre. There are no fetch quests, and they don't heap you up with oodles either. You go to a village, they'll have one questline for you and it's usually pretty interesting.
There are quite a few bad things about this game though;
The pvp isn't too good. It's fun if you like siege combat. But it still is laggy. And it takes a while, 30 minutes or so, to actually get to the battle cause the pvp battlefield is HUGE. There isn't any other pvp, so 1v1 isn't really ever going to be a thing.
The group finder system is totally broken. I used to turn it on for a few hours a day, but I never found anyone.
After you beat the game, the end game isn't too good. I mentioned the questing is phenomenal for an MMO game, however that's about all their is. Since the pvp isn't too good, after 50 the game tells you to start going to every other alliance and doing their quests too. Plus, the characters are mostly all shallow, with boring dialogue.
There is also an issue with role playing. Every quest has you as the only one who can fix things, but there are usually others right their doing the exact same thing as you. Plus, why am I going to the other alliances to help with their crap now? If i'm a nightelf I can't imagine why I'd want to go help the bretons.
There are other smaller issues, but the lack of things to do after level 50 drove me away. However I did spend 100+ hours to get to 50 and had a blast doing it. I would definitely recommend this game for that.