Limited testing here, but sort by ratings seems like it might be inaccurate. With a test set of three listings, a 1.5 star, a 3.5 star and a 5 star, regardless of which way direction, the 5 star was popping up in between the others.
Reviews might have the same issue, but my test set was fairly limited on that. Since I’m dealing with one test listing and the rest are real, not wanting to clutter things up too much more there with more indepth testing.
Listings without any results also end up on the start or end, depending on the direction you are going. Maybe that’s okay, but I wonder if there is more value segmenting these by has rating/review and hasn’t, and you sort by the has, either direction, and then follow up with the hasn’t, which in this case isn’t really a high or low but a null value.
Cheers