We had an Aria II deluxe with electric flushing. It was noisy from the day we got it, and finally it started not flushing except manually. Replacements parts were very expensive and we hated the noisy flushing so we looked around for a solid porcelain toilet to replace it. It turns out while some have a porcelain bowl, but still had a plastic base. We wanted one with a solid porcelain base as well.
We finally found the Aria Classic with a manual foot pump. It is solid porcelain, including the base. It's so much quieter and looks very nice too.
http://www.thetford.com/HOME/Products/PermanentToilets/AriaClassicwandwoWaterSaver/tabid/86/Default.aspx