as the one who started this thread..
I have come to understand the differences. It is in the silk reeling. Chen uses a more spiraling and complex delivery of power with tan tien more like a spinning orb than a point to be moved in a linear direction. Power is brought up into the back and delivered and grounding is maintained through the Gua (inguinal cut). Direction is more from the waist and less from the hips, this is a subtle difference. Overall it DOES seem less relaxed than Yang, but then I am a beginner. ..and I don't like the footwork/stances as well as Yang. Just my report from my cross training experience.