Hmmm. I'm an OTPer to the extent that I'd rather read McShep than gen, and John and Rodney are my favourite characters. That means I like seeing them with other people, if they're happy/stable (which I don't necessarily think they *would* be together). I'm actually sad when an author breaks up a viable pairing just so John and Rodney can get together - sometimes I just don't buy it. I'll read stories focusing on either of them, John without Rodney moreso than the other way around because Rodney's really come into his own on Atlantis and it's difficult (and sad) to imagine him without that influence. I really like the stories where they've stayed just friends because they tend to have greater emotional complexity - for example, the author has to deal with how close they are and address their partners' insecurities about that.
I happen to think that John and Rodney, as a couple, would fight a lot, and would be more likely than not to break up because they don't have the emotional tools to fight constructively; they hit below the belt, and they (sometimes deliberately, if they're feeling trapped) take things the wrong way, and most of all they have a tendency to run away instead of staying and working things through. That, to me, gives them ongoing tension, even in established-relationship fic, which is what brings me back to McShep time and time again.
Wow, I'd never really thought that through before