ciomalau: in skyrim with the latest patch you can gain infinite levels by making skills legendary but in oblivion you can't do that. especially if you set the game to be more difficult you hit the caps pretty fast. but i know there's a lot of mods for oblivion and i didn't try too many. the only mod i liked was one to give me more carry weight so i don't have to travel back and forth to dungeons in order to sell my loot. is there mod in oblivion to give me something like a permanent benefit for reaching 100 and then to make the skill noob again so i can continue gaining levels? like the way it happens in skyrim?
Others have given the reasons. Personally I would say never pls vanilla oblivion. It is ridiculous, bandits in glass armour etc. At minimum you would want Oscuro's Oblivion Overhaul which deals with the levelling and fixes monsters and items to places rather than level.
TBH though, you will most likely want to pile on a ton of mods, city improver, better graphics etc. Take a look at nexus mods to start with, for a fair few you can use the nexus mod manager, its simple and basic. Later on look at some of the mod compilation pages, e.g. Google oblivion mod list 2015. There are lots of lists of mods and how to add them in. Its a big subject. Many, many mods out there which can alter everything. Its the best bit about ES games, they provide the engine and the community provides the game.
As for Skyrim, there is a mod on nexus which grants a +5 to the skill for the perk point so that it does impact the character, however the whole levelling thing is just as bad in skyrim as oblivion, and the game itself pretty bad being a console port, I.e. Needs lots of mods to be playable.