Well, I wholeheartedly agree!
A 'typical' RV toilet is a gravity thing; it's intended to sit over the top of the wate tank underneath. There's typically a foot valve at the base of the toilet; rasing that will put some water in the tank for use, pressing down on it will open the slider valve and allow the waste to fall into the black water tank below.
These toilets are available from (relatively) inexpensive all-plastic units to very expensive all china and super fancy units. I think most folks will find the toilets that are listed as having a "household" sized bowl more comfortable. I got a Thetford Auqa-Magic Aurora with a china bowl because I thought it would be easy to keep clean and might not stain as easily as a plastic unit. I don't remember precisly but it was something just under $200 or so. You can get something like a Valterra "La Toilette" for under (or around) $80...it's all plastic. You can get a Thetford Auqua-Magic V which it sized much like a home toilet and is typically operated with a hand valve for maybe $125 or so.
Marine toilets, on the other hand, are not typically situated over the waste tank (that would be under the boat!) and instead rely on pumping the waste from the toilet to the holding tank. Some are manual and operated with a hand pump (pumping up and down, or back and forth), others are electric and mimic the manual motion or use a macerator pump to chew up the waste into small bits and also pump it to the holding tank. These also come in "compact" and "full size" models to accommodate different space requirements. And, they also range from low price (manual, compact, plastic model) to absurdly expensive.
The advantage of the marine toilet is that it can pump the waste to a remote location when siting the toilet over the tank won't work and with the electric models flushing is just a push of the button. The downside is they're finicky...a wrong "something" (such as a sanitary napkin) will plug it up big time and clearing the problem is not a fun task whatsoever. They also have components that require periodic maintenance.
The advantage of the RV toilet is that it's simple and all but impossible to plug up. Even with the water line broken or no power available it can be used; assuming you have some water in jugs or a bucket you can dump some in the bowl, use it, and flush it by stepping on the manual slide valve. Simple is good! The disadvantage is that it needs to be over the holding tank (or close enough that a pipe doesn't have much of a horizontal run).
Finding one that's comfortable, I'm afraid, is a matter of personal feel. Just as in home toilets bowls come in all shapes and sizes as do the toilet seats. One size doesn not fit all so I think you'll just have to look for "full sized" or "household" sized units and make your best judgement. And that, as they say, is the bottom line (I'm sorry...I just couldn't resist!