As with Morrowind, I was engrossed with Oblivion for a while but didn't have the will to finish the main quest. The leveled enemies made adventuring easier but took away the fear of straying off the beaten path in Morrowind - and after reaching a certain level seeing the same cretins all the time in the oblivion realm got old, fast.
It is a pretty game, and the combat is pretty fun; but I had very high expectations and it didn't really keep my interest long term. One thing I didn't like was the lack of diversity, the cities didn't have as much variance as in Morrowind, some of the guilds weren't as interesting, I liked the whole house redoran/hlaalu/telavi system in Morrowind. In every town in Oblivion I swear they used the same tree in a circle as a centrepoint of the town.