I've played Daggerfall up to Skyrim, also ESO. I enjoy all of them, though whenever I return to Morrowind, I almost never finish a playthrough. The last character I created was an Imperial Bard called Toby Fox. That was on my old PC so I think he's gone forever.
Daggerfall is fun, I go back to it now and then, selling loot from dungeons for loads of money is the most satisfying part.
Morrowind is mixed, I can enjoy it, but the RNG combat is horrible. If anyone knows what mods to install for my next Morrowind playthrough, please leave some links, thanks.
Oblivion was fun, but it has been a while since I played it, I liked the Dark Brotherhood and Mages' Guild questlines the most. I also like the way the magic worked in it compared to Skyrim, rather than equipping a spell in your hand, it basically stays in a back-slot you can activate whenever. It mixes better into the fighting.
Skyrim, although limited on the roleplay side, is very fun as well. I do wish they had done more with the questlines as a lot of the questlines were very basic. The best ones are the Thieves' Guild and the Dark Brotherhood. I also remember that murder investigation quest in Windhelm quite strongly.
Elder Scrolls Online was a fun time-sink. I think the crafting is at least something future ES games should take on board, I liked the variety of styles of armour and weapons. Though, once you've done all the quests and whatnot, the only thing that's left is PVP which, from what I played of it, I did not like very much. For whatever reason, the PVP and PVE skills aren't separated, meaning that the devs would nerf a skill for PVP and end up making it unbalanced in PVE and vice versa. Though, a guy I used to watch called Zharic Zhakson doesn't like ESO very much since he thinks it retcons a lot of stuff and doesn't make sense lorewise.