I use them. They do keep pretty clean but I take them apart once a year and make sure they're spotless, which is a bit fiddly but I don't mind doing it. The spacing seems to stay accurate. I have to arrange the frames the cold way but I prefer that anyway. I really have no idea how much difference it makes to Varroa numbers as I've never used any other floor but I do treat for it anyway. I have fairly low levels but maybe I've just been lucky.
I've used them for 9 years and as I have a big Birthday coming up shortly I'm getting another hive as a gift. My son is paying for a Happy Keeper floor to go with it but he is well off and I am not. It would be interesting if anyone has compared how they perform alongside an OMF. I'd love to know if there's a real difference.
