What you have read is correct, but it is relative to WILD musk turtles. These guys adapt so fast to captivity you would be amazed. Raising a hatchling is particularly satisfying, as they show fear for such a short time, then realize you mean food and will start following you around the tank. My spotteds are still secretive and retreat from me, but muds and musks I've kept learned not to be really fast.
Musks will make stink, if they are wild ones, until they learn to be comfortable with you. This is really not a big deal, and it might happen to you once or twice if you get a wild caught animal. If you get a hatchling, it will never happen.
As for biting, I've had little ones try to nip me, but they quickly switched to just gaping (opening the mouth in a threatening manner) then stopped even that. In any case, they are easy to handle without getting bitten (softshells and snappers are the only ones I worry about bites from). A full grown musk can give a nasty pinch if it does get you, but it will most likely not break the skin, just scare you (I still yell "ow!" if bitten by a turtle, even though none of mine can even make real pain). I've had oversized painted turtles hanging off my finger when they accidentally bit it instead of the pellet I was offering, and while it's a shock, it's really not painful.
Musks can be aggressive, but it is usually only in the sense of male-male aggression in their species, or accidental biting while eating. I've not noticed aggression otherwise, and many people keep them with other turtles. Any species can be like this. Even male spotteds will battle. If you get a hatchling and raise it, then are able to determine the sex, and you want to get another of the species, just be sure to get the opposite sex, or have two females.
You are right on spotteds cost. Their small size (same as muds/musks, but not needing a large land area in addition to water) makes them sought after as pets, their colors help.
Loggerheads are pretty animals, especially if you get one that keeps it's juvenile coloration (some people believe that lots of snails and crayfish and such in the diet will help this). Their big heads and constant trundling along the bottom of the tank are really an interesting thing to watch. With them, also, you can have a very small basking spot and devote the rest of the tank to a large expanse of shallow water with driftwood, plants, and such, which they will love.
I tend to disagree somewhat with the info at the link you've provided. It just doesn't match up with what I've experienced, and other keepers have.
It's true they might not be as attractive as a spotted, but I truly think they make a better "pet".
Whatever you decide, you will likely enjoy the pet. I know of nobody who did not like the musk turtle they had. Just remember if you get a spotted that you need to create a land area of good size for it.