I know yang and some of his long term students. There was a link across my deceased sifu when yang sought him out.
Yang teaches his branded mian quan. It's all drills no form chains which seems to differentiate him from another mianchuan I saw that taught chains of moves earlier on. Plus he does less footwork. The moves are all arcing attacks & are mainly arm (elbow/fist) based. There's also a big focus on body pounding conditioning with a partner & a sand bag for hands. As mentioned above - leg work and kicking are limited. No sparring except for seniors and it's limited.
Yang also mixed in a few other things like chinna and taichi. He also speaks english well and likes to emphasise internal terminology like breathing and feeling the chi. I guess that appeals to some more than others.