And... we just got rid of ours, as neither of our cats would use it, instead preferring an upstairs water dish. We'd used it for years, and knew they weren't using it "much", but after watching more closely for a while, we realized they basically never used it. Replaced it with a regular water dish and they're drinking all the time now. Note - they were drinking before, just had to trudge upstairs each time.

But... earlier generation of cats used the fountain. Seems very cat-dependent. I suspect had we only had that option, they may have used it, but didn't want to test that level of harshness.