Put it this way I love Bioshock but I hate TES. This is because I do not like RPGs, primarily because I want a story with direction and I hate levelling, grinding etc.
As has been said they're different types of games, to put in terms of series you will probably know well: Bioshock is Zelda and TES are Final Fantasy. Basically, if you like to know where you're going, why you're going there and to not have to debate the pros and cons of hundreds of different items RPGs, like TES, aren't for you. Of course lots of people like both and to be fair action/adventure and RPG have a lot of crossover so I can see why you asked this question.
Basically go play a friend's copy see if you like it, but when it comes down to it RPG's are for people who like customisability and full control of most of their gaming experience if you prefer just chasing the main story and going with the flow then you may find TES tedious, obtuse and annoying.
As has been said they're different types of games, to put in terms of series you will probably know well: Bioshock is Zelda and TES are Final Fantasy. Basically, if you like to know where you're going, why you're going there and to not have to debate the pros and cons of hundreds of different items RPGs, like TES, aren't for you. Of course lots of people like both and to be fair action/adventure and RPG have a lot of crossover so I can see why you asked this question.
Basically go play a friend's copy see if you like it, but when it comes down to it RPG's are for people who like customisability and full control of most of their gaming experience if you prefer just chasing the main story and going with the flow then you may find TES tedious, obtuse and annoying.