I can only speak to the brand we decided on, but here goes: We, two to four of us, have gone two whole seasons, all year round, without actually emptying the primary solids container. See also, kitty litter scooping, which we, as servants to several cats over the years, have dealt with. The C-Head cleaning is lots less objectionable, as there is still no odor, except that of the fiber/peat/sawdust. We add more sawdust as we remove the solid waste, or when that solid waste isn't. Most people, I think, go a month or so, then dump the whole shebang into that secondary bucket that comes with the C-Head when the agitator gets hard to crank. By then you're moving a bunch of fist-size balls of mostly fiber/dried poop around. That second five gallon bucket can go several months before running out of space. Eventually it's time to dump it into a doubled kitchen trashbag, maybe with some Clorox, or other legal disposal option, but nothing like the every-weekend pumpout time-gobbler.

We empty and rinse the pee-jug as soon as it's practical to do so, daily, when possible, as that is, frankly, what can get odoriferous after a while. Some people add septic-tank chemicals, sugar, dish soap, etc to their stored jugs, but frequent emptying works fine for us. I wouldn't want larger jugs (heavy and awkward for me when full) or expensive proprietary ones, because eventually the jug gets shabby-looking, I'd just as soon toss it out then.

I understand that Sandy at C-Head has designed larger containers to go below decks, for long journeys. I'm not tempted, but I'm sure others would find it useful.

Our 6 to 9 year-old grandchildren have had no trouble with it. Of course, the little boys can go aim off the lee rail, can't they? Not sure how a 2-y/o would handle it, but probably ok. The fore and aft design seems to work well with the way people are plumbed. The only people I've heard complain are chubby older women who may not produce a very strong stream of urine, and the dribble-back can cause difficulties. A little hands-on problem-solving produces good results, they tell me.