Depends on what you value in these games. I played vanilla Morrowind again after Oblivion and still enjoyed it a lot more for the exploration and such. The areas in Cyrodiil were boring for me. Towns were boxed off and it felt like a giant field with some interesting places that sprout out. I don't know if mods fixed it and a while ago I was meaning to play it with mods to see if my opinion of it would go up. I may sometimes seem like I hated it, but I did enjoy it for the most part.
Vvardenfell in Morrowind was a pretty great world. You can walk in any direction and find many interesting locations on your way. When you reach major areas, they too don't just feel like the same place with a difference design. You a prison that floats in the sky and things like that. First time I played the game and got a scroll that makes you jump incredibly high into the air, so I stood in Balmora, ran and jumped. Landed near a house with a bunch cultist. And that's another thing, Oblivion didn't really have cool magic spells like that. It was all really tame and limited what you could do.
Just about the combat, while Oblivion is better, it isn't anything near good. I'm not playing these games for the combat and would rather go with the game that has more strengths than weaknesses. The reason Fallout 3 was such a surprise was because VATS let me mostly ignore combat and focus on the exploration and going on quests, which were great this time.
btw, if you want to use mods in morrowind, there are a bunch linked recently in the what are you playing thread.