All the recommendations appear to be from folks who've had theirs for more than a few years....so it's worth noting that ITT spun Jabsco off a few years ago to a company called Xylem Flow Control, who has manufacturing plants in 3 countries--U.K, China and Mexico. All Jabsco products sold in the U.S. are now made in Mexico with material, parts and equipment sourced from China and other Asian sources. Which may explain why most of the reported problems with the Quiet Flush series seem to be focused on newer units.
The top rated electric macerating toilets are the Raritan (the only mfr who still makes everything in the US) Marine Elegance
Raritan Marine Elegance Owners Manual and is their SeaEra, which available as either a complete toilet or a "conversion" (everything but the bowl seat and lid).
Raritan SeaEra Conversion Promo Sheet (Raritan is overhauling their website...I've provided links to the pages that provide the most information.)