What gave you the idea that a PH II costs $500?
It's the best toilet UNDER $500...for only about $200...and will provide at least 20 years of trouble-free service if it's only kept properly lubricated and rebuilt every 5-6 years for a cost of about $50. Or you can keep laying out $100 for a new Jabsco every couple of years that may not even remain trouble-free that long. It's price, not quality, that makes Jabsco the choice of most production boat builders (if you can buy one retail for $100, the OEM price can't even be half that much). When the sanitation "system" consisted of only a toilet, two thru-hulls and a little hose, they could afford to install better toilets, but holding tanks, y-valves, macerators etc have increased the cost of toilet facilities by 500% or even more, but they have to install 'em. So they use the cheaptanks and hoses they can find Only high end builders like IP and J-Boats are willing to put any money or even any real thought into a sanitation system...it's just a nuisance to be dealt with as cheaply as possible.