They do feel quite different. Oblivion was my first RPG and my first Elder Scrolls games, and it has an odd skill system. Other than that if you can get over the outdated combat etc then I believe it's a brilliant game, I managed to visit every dungeon in Skyrim, something that I actually never managed to do in Oblivion. It's big and it's fun, if you've got a lot of free time you can become well immersed. Also PC users can play Nehrim which is some golden German fun.