Do the toilets you have include SanaGloss? That can really help. It's not available in every color, so that may be the missing part. The II versions of the toilets have the dual cyclone bowl wash, which improves on things, but Sanagloss really does make a difference, regardless. Some peoples' diets can result in very different end results when using a toilet as can how you sit on the thing. Ideally, you sit way back, which directs most stuff into the water spot, rather than the front slope, and that helps keep things cleaner.