Oblivion pros
More interesting main quest
Class and starsign system
More varied and interesting world
Two chances to edit character
Game pauses when talking
Skyrim pros
Better character creation
Better levelling system
Better magika combat
Bashing
Civil war
Inb4any other Bethesda games
Inb4dark souls
Inb4anything else
-
I like Oblivion more. Skyrim's main quest and DLC's were better, but Oblivion's world was more varied with it's quests, customization, art direction, etc., which prolongs interest. Regardless, I can barely play either of them for five minutes now without getting bored. I'll make it out of the prologue and "well, I'm done for now."