I agree with razakdigital that a background in Lohanquan helps undertanding of Yin Fu Baguazhang. It provided the martial context from which these guys went internal. It was the basic skill upon which their Bagua was built.
In terms of application tendancy I also feel that Yin Fu differs from mot other Bagua. Cheng Tinghua was a mid-range grappler and it shows up in the form, which includes many more throwing set-ups than the Yin Fu style. As blacktaoist said "explosive and aggresive attacks of piercing palms." When I asked my teacher about throwing he said "In this style you don't worry about throwing him, just pierce. It doesn't mean you can't throw but the pierce is the primary weapon."
"The heart of the study of boxing is to have natural instinct resemble the dragon" Wang Xiangzai