I noticed something rather interesting. Slimmer, more stylised dolls like RingDoll look rather graceful in a 3 part torso with a mid-torso joint while plus sized, more realistic dolls like Iplehouse tend to have only 2 part torsos with an underbust joint. Do anyone ever put into consideration the body type and the type of jointing used?
I find the under pec joint seems to be really good for shounen manga char poses and some model poses, but are useless for poses where the middle part of the spine has to bend (like fetal or sitting slouched). Minifee boys manage this pretty well. But I can't think of another example, off the top of my head. The "follow the bottom of the ribs" type joint, my best example is dollstown 15b. You can sit slouched and to a certain extent do fetal positions. But if you're not careful with the design of the joint...or if you try to pose it beyond the design allows, your doll will end up looking like it has a broken back. The bottom of the ribs joint seem to work better for dolls whose back is not extremely concave, so this might explain why slimmer dolls seem to get away with it better. To get around the broken back problem, you pbb have to make a tummy joint or a granny panty joint. But I haven't seen a pretty manly example of these.
Personally, I just like the split torso with the peanut knees. With that lower hip joint you get more poses, but you have to cloth them more.