I just recently bought Oblivion and have to say I was very impressed with it considering the game is actually older. I got the game of the year edition and love it.
The game doesn't have the best graphics but it doesn't have the worst graphics either. Sometimes when too many enemies are in one place or too much is going on the game slows or stalls and sometimes freezes so I recommend refreshing the ps3"s RAM every once in a while if you plan to play for hours.
I played as a sorceress basically and a Mage Guild member who has access to some great features like making my own magical items, and creating spells. In general the game has tons to do, in fact I've only done about two of the mains story quests and I am three months playing the game already. I've been playing basically all side quests and the extra quests included with the game of the year addition. Clearly if you want an RPG full of stuff to do this one will not disappoint.
Some things I liked:
1: Ability to use magic always a plus for me.
2: Ability to self guide where I wanted to go and to do side missions when I want to do them and not be stuck in a linear process of where and when I can go.
3: Huge areas to explore
4: Being able to buy horses and houses to keep my stuff in.
5. Collecting ingredients to make potions (even though the potion making is difficult at best)
6. Lots of types of armor and weapons to use and the fact my sorceress was NOT limited in what kind of weapon or armor she could wear.
Some things I didn't like:
1: The menus, ugh the menus were very weird and clumsy to navigate.I still feel like I can't barely work them right.
2: No mini map, you constantly have to look at the menu map to see where you are.
3: Creatures/characters constantly attacking my horses. It seems that enemies are auto-attracted to killing my horse first and fore most, very annoying because you can't revive dead horses.
4: Some of the missions have a severe lack of guidance as to what you're supposed to do and how, while others are very clear.
5: Constantly accidentally stealing things is way to easy to do. I sit in a chair and try to get up and my character accidentally steals a cup. I try to talk to a store owner and accidentally steal a book on the counter.
6: The pilgrimage of the Nine. I am very annoyed that in this game you have infamy and fame and if you are not a complete angel in the game or if you can't stop accidentally stealing things you have to basically run around to the un-mapped shrines of the nine over and over again to gain their blessings in order to wear the Relics of the Crusader. I finally just got sick of looking for them and stopped caring. I can just wear something else.