they're pretty different from Hiveworks, at least from what i know. HW pays their creators from advertising, but it doesn't seem like there's an actual sense of community in HW. with Spiderforest, i believe they're a lot more community oriented, but don't pay their creators. i was rejected by Spiderforest a couple years ago, but i definitely want to apply again, since the last time i applied i was only like... less than a year into my webcomic. i'd vastly prefer SF over HW just because of that sense of community.
EDIT: SF also isn't a stickler on exclusivity, so you can have mirrors of your comic if you wanted to. meanwhile, HW requires exclusivity.