Count me in for the airhead also.  Ennis Kay

Before anyone gets too excited about an Airhead group buy...I recall someone posting that the owner of Airhead would not agree to discounted group buys because he had plenty of business and so did not need to. 

Talking to channel cutter yachts nature head distributer in Canada, if there are five interested in Canada he would pay shipping, not sure how this would help those south of the border, probably best for me as bringing stuff north usually has duties added, I will probably order mine over the summer as I am just about ready to start working on my head.  Nick

If this thread isn't too old...I am TOTALLY in. I just got rid of my foul , old , marine toilet and associated parts.

That C-Head looks pretty cool. I like that it uses a common 5gal plastic bucket and 1gal water jug. For a little more than half the price of the others, I think one could live with the smaller capacity and more frequent emptying. I can't see storing full containers on the boat though, but it's nice to have the option.  I  think you'll want to go with the optional ventilator, especially in the confined space of a boat.

I got a Nature's Head a few years ago mainly because it was the only one I was able to examine in person on a friend's boat. The slightly larger footprint was not an issue on the W32.

To address some of the comments in this thread regarding the Nature'sHead, I would say that in removing the "liquids" container, one only needs to partially lift the lid 1/3rd of the way, no "yuck" factor and no bolts to remove. One understands the reasoning of the molded seat if you've ever used the hinged-lifting type seats while being tossed about in a sea--sitting or standing. (A simple fix is to attach "cleats" under the seat inside the rim to keep the seat centered). When I feel the need to "stand and pee like a man" (as the Airhead maker puts it), I can simply go to the lee rail.

Athough there seems to be some "differences" between the AH and NH makers,  I think the differences between the products are small and inconsequential.

 So far we've cruised with 1 - 4 people on board for long weekends and 1-2 week cruises  using shore facilities when available. Compost gets changed out once mid season.