I got her with a Song body (didn't like the ears for my elf queen.) She's my first MSD, the first resin I ordered in fact, though I got a BBB Elfkin from Junkyspot on an impulse since I just couldn't wait to get my girl from RS and had to have SOMETHING. The RS order took less than 30 days from order to delivery.
Here's my unboxing on Flickr showing some posing:
http://www.flickr.com/photos/dhawktx/sets/72157624371673535/I wasn't sure about the upper joint either, but have been very pleased with her poseability. The joint allows her to cock her shoulders to one side or the other, and to arch her back a bit. In fact, she WANTS to do all of the above! LOL! I have to let it cock to the back until I can mod the Song head as it doesn't want to tilt back. Just got an An floating head - its mobility is just fine so I need to compare the two and get the dremel out.
This shot shows the bust AND waist joints at work:
She is ever so slightly taller than the RS or BBB girl bodies. Her hands and feet pose better since the ball is larger, lifting them out of the wrist joint. The top knee joint is a bit kicky - wants to go from straight to 90 degrees with a POP!
Here's another shoot I did (forgive crappy photos please, still learning!):
http://www.flickr.com/photos/dhawktx/sets/72157624508213008/Her hands are quite expressive and she stands easily. In this shot her upper joint had popped back again.
She's an amazing doll and I look forward to finishing her!