Hey Tom,
I was taught in Beijing with an incredible eye for detail. My teacher was extremely technical and would constantly correct our movements and explain the application or context. We also trained very intensely, 2-3 hours a day 4-5 days a week for just about 8 years.
The main elements that distinguish Beijing style from the others, at least in my opinion, is that the Beijing style really emphasizes the principles and technical aspects of the movements. When you train your solo movements it is incredibly clear what you are trying to do. It is not about learning a form, it is about developing the proper connection, strength, relaxation, coordination, etc. It is a quality of movement you are looking for. Beijing style probably also places the most emphasis on the technical details. When studied deeply you know what every part of the body should be doing, what principles or energy you should be embodying, and what should be happening to your opponent.
In my experience I have found that Beijing style has much more in common with Tai ji, Ba Gua and Xing Yi then it does with something like Long Fist or Shaolin. I don't believe the same could be said for the Baoding style, in fact I would say just the opposite.
You can also check out my Shuai Jiao specific webpage
www.guangwushuaijiao.org. It has some videos and other information about Shuai Jiao as well.
Thanks again and I appreciate the support.
-Sonny