The Raritan original series "Compact" manual marine toilet has been discontinued since 1991 - parts for it are few and far-between. Raritan's "Compact II" was also discontinued at the end of 2010, however most of the replacement parts for it will remain availalble for the forseeable future.
There are scads of earlier postings here from other boaters about the Jabsco manual toilet, most of which are not favorable. And there's also Peggie's opinion of them, stated on many, many of the earlier postings - there's a reason why the Raritan unit is more expensive...
You get only what you pay for - if you take the cheap way out, those will be the results you get.
The Raritan PHII and PHC toilets, if properly maintained, will last 20+ years. But proper maintenance is the key. I get calls all the time from people asking why this or that isn't working, why their toilet won't bring in water, or won't pump out water. When I ask how old it is, and the last time it was rebuilt; you'd be amazed at the answers I get. "Well I've had excellent use of it for the past 9 years, and now suddenly it isn't working right..."
"But have any of the consumable parts been replaced in all that time?" I ask.
Dead silence.
These are not household toilets with virtually no moving parts, that will last for 50-75 years before needing to be replaced. Marine toilets are basically nothing more than two pumps, that draw in outside water, then evacuate the toilet bowl and pump its contents to a remote location, usually a holding tank. The parts inside wear out and must be replaced periodically. The joker valve for example, should be changed every year; or at the outside, every other year. Seal kits should be installed at least every 5 years, and doing it at 3 year intervals would be even better.
I once knew a man who was an over-the-road salesman. He bought a new car every 3 years. During those 3 years that he had it, he did absolutely no maintenance on it whatsoever. He put gas in it and ran it. He'd occasionally check the oil and would add a quart every six months or so, and that was it! He claimed that it was cheaper for him to do it that way, than it was to do the routine maintenance on the car. Maybe it was cheaper for HIM, but I sure wouldn't want to be the next owner of that car...