I love them both, really. Fantasy tends to bore me, though. there's always two dozen gods, some good, some bad, a mix of races, with tension between them and everything, some guilds here and there, different schools of magic, etc... I just don't remember the last time a Fantasy Game really surprised me at all.
That's why I like Sci-Fi more. There's always new, interesting technology, they tend to have more shooter action as well, which I always like, and all sorts of interesting landscapes to explore, thanks to the possibility of space travel.Except for Fallout, though Fallout makes up for it with its own charm, and delightfully diverse characters.