I agree that things that work in short stories don't necessarily work in longer stories. I'd be wary about buying a novel if I saw that it was in the present tense, I think, but would be quite happy to give a shorter story a go. It also depends on the mood of the story, I think... and also, perhaps, on the viewpoint character. Some viewpoint characters just lend themselves to present tense narrative, but others feel much more past tense. I think it depends on how reflective the character is, and how much they seem to act on instinct, or live in the moment.

Rambling now... ;-)