I think I stress over this way too much. Of course, could be a make or break issue in terms of editorial taste, hence the stress.
Benefits of past tense:
1. Friendliness in feel, whereas present can seem aloof.
2. Closeness to narrator. For some reason, stories told in past seem more intimate. Present tense can make a story sound detached.
3. Tradition... [cue song from Fiddler on the Roof]. Tradition!
Benefits of present tense:
1. Immediacy of story--no one knows how things are going to turn out because it hasn't yet happened.
2. Detachment from painful material. Like, are the emotions too raw? Too hurtful to deal with? Present can be an emotional filter of sorts.
3. Seriousness of tone. Some people think serious subjects should only be dealt with in a more literary voice. Present tense is not "airy" or "light."
Still haven't completely made up my mind. I was writing the new story in present, but I'm thinking about switching over since the theme's so edgy. Yes, this kind of contradicts what I've argued above, but the main character does something in the story a lot of people will find unsympathetic, so I want to make her as close and likable to the reader as possible. That way, maybe the reader won't be too quick to judge her actions.