Played a lot of them RPGs during my lifetime and I do enjoy the genre greatly (Neverwinter Nights, Gothic series, Diablo series, The Witcher-which i might finish one of these days, KOTOR-but just the first, the second one of the series managed to piss me off and so on).
The greatest appeal of the genre lies in the fact that if immersion is good, you enjoy wholeheartedly the story, you attach yourself to your character more then in any other game, you get drawn into it extremely well. The only problem I would have with the genre is that there are to few games out there which have the "perfect lenght". Some are either too long (Dragon Age Origins, Baldurs Gate etc) while some are too short although some might argue the contestant i've decided to put up - Fable, which would give you roughly 4-5 hours of gametime. I'd like at least 15-20 fun hours for my money, not something that would last like the time period of an AIDS test >_>