@Summer64 If you feel that they were good folks, but not suited to sharing a home with others, please do make that evident somehow in your written review, for the benefit of other home share hosts. Some people would be perfect guests in an entire place listing, but just don't fit in a home-share model, either because they aren't really aware how their behavior could be affecting others, like leaving their stuff laying around in communal spaces, or don't have great social skills, or disrespect your time and boundaries, as in a guest who seems to think you have nothing better to do all day than sit and listen to them talk about their personal problems all day.
If you really feel that it was just a personality conflict, that they weren't the kind of people who you could easily relate to, had a much different lifestyle than you,
then that would warrant just a straightforward review as to their communication, observance of house rules, cleanliness, etc.