I'm a bit weird. I like Snape a lot more in Snarry fics. I enjoy his snark and sarcastic wit, and am generally a bit more interested in what's going on with him than with Harry. But, if I was going to read a non-Snarry story, I'm much more likely to choose a fic with Harry paired with someone else than to read a different Snape pairing. In the end, I think it is the interplay specifically between Snape and Harry that makes me like both characters so much. One without the other isn't as compelling to me.