I think kunlun/yi gong is a very beneficial practice, it really adds a layer of depth to my other qigong and meditation practices. Seeing the form in the formless and the formless in the form helps bring me closer (still a ways to go...haha) to the wuji state. I think eventually the formless/spontaneous practice can be all that one needs but a solid foundation in qigong and daoist wisdom traditions is very helpful before one can leave all forms behind. Maybe many never get to that point, and its not a point for all, but developing awareness, training the mind, and developing intuitive knowledge are the biggest benefits of the practice for me.
Other practices in kunlun system are also quite good and powerful; individually I could recommend all of them. The only downside from my perspective is too many practices - better to pick one practice and do it daily, learn from it, rather than sampling from the buffet table of spiritual practices.
Also for me I like to see an emphasis on body-mind-spirit all in balance - to that end I think it is important for practitioners have or work to build a solid foundation in qigong practice, theory, and history before putting all their eggs in the enlightenment/attainment basket. I think many will find this basket isn't as important/appealing to them as it once seemed.
Oh yes about mixing practices - the spontaneous practice helps build awareness and intuition and will make it clear to most what practices are compatible and which are not - for me it blends very well with internal martial arts, qigong, and many meditations, daoist and buddhist. Red Phoenix seems a little more picky about what you mix it with. I stick with he spontaneous practice for myself, although I am always open to learning about other energy practices to help gain perspective and insight on my own practice.
