Well, I'm perfectly happy with the original galley maids using seawater. My previous boat used fresh from the water tank and I didn't like using up FW for that purpose. We haven't had any problems with head odor at all but maybe that's because the water here in LI sound is not too warm and I clean the heads every week or two - 5 minutes with a rag and some vinegar. Incidentally, I NEVER buy "boat cleaning" products - they are like buying "boat toilet paper" - money for nothing.
When we first got the boat, I seriously thought about switching to modern heads/freshwater but the oems are extremely simple - no moving parts in the head itself - and work well.
Of course, the amount of water per oem flush can be an issue depending on how many people are on the boat, where you are operating, and the size of the holding tank(s). There are only two of us on the boat 90% of time so this isn't an issue for us at all. All three of our heads' discharge are processed with either Lectra San or GM chlorine waste processing systems. So the odor associated with waste is eliminated since the bacteria is killed. However, given enough time without pumping, I assume that bacteria will reestablish in the holding tanks.
On a related item, I have always been amused by the concept that you can legally pee (or whatever) over the side but you can't do the same thing in your head and flush it even though it ends up in the same place. That being said, I am not proposing that everyone should do their business over the side! BUT on a further note - that's no more bizarre than the fact that commercial treatment plants dump effluent into Long Island Sound while, at the same time we are not legally allowed to dump the waste from a Lectra San which is cleaner than what the treatment plant is dumping. I realize there are issues involving the fact that treatment plant output is supposedly monitored/certified by somebody while the Lectra San operation/use is not. Seems an easy thing to accomplish with a periodic required check...
Uh, oh, I see I'm getting perilously close to stepping onto one of my soapboxes...
