Would you prefer Namor to be in the X-Men, F 4 or the Avengers Universe
He would be so much better in the Avengers Universe but knowing FOX and their eager to rise above Marvel Studios, they'd probably claim him first - I'm pretty sure Namor has rights issues similar to Quicksilver and Scarlet Witch:
Namor is constantly referred to as the First Mutant and has a connection to X-Men
Has a mild connection to the Fantastic Four
And also has a connection to Cap and the Avengers
I would prefer Namor in the Avengers Universe in terms of quality
I would prefer him in the X-Men/Fantastic Four Universe in terms of interactions/dialogue (btw, FF and X-Men exist in the same movie-verse thanks to the asshole that goes by the name of Mac Miller I mean Mark Millar).
I think it depends with what they do with him. So far, I haven't seen the X-verse have a necessary heavy bruisers outside of Colossus and Juggernaut, and the latter is the only one they really done got to show off. So putting Namor with them would give them a power man or they would need to use one against Namor.
FF could be fun if they play the classic role of Namor trying to get Sue and him hating surface dwellers. A little old school, but doable and the Thing is a bruiser, so we could get a nice slug fest out of that or some good flight fights with the Torch.
Since the Avengers already do have some solid strong men on their team with only more to come most likely due to the different phases, it will be interesting to see where they would put him. I mean, they already have Thor, Hulk, and Iron Man, so if he gets put on the team, how big of a role would he necessarily play?
If I had to pick, I'd probably like to see him in a FF movie.