When I first became interested in T'ai Chi, my initial experience was from a book by Cheng Man Ching which I bought in a secondhand book shop. I started teaching myself his form as envisaged in the book, but found that the book was not as self-explanatory as CMC claimed and in the end I had to buy more and more CMC books to get different perspectives on the points that confused me. In the end, I acquired I think nearly all of his published books on T'ai Chi over the course of a year or so. However, I grew disenchanted with the brevity of is form and sought a teacher of the Yang Cheng Fu long form. After a number of misadventures I found Grandmaster Lu Jun Hai in London and I have learned most of my T'ai Chi from him.
I have to say, as a result of my experience of the Yang Cheng Fu form, I am no longer any great admirer of the Cheng Man Ching form. His stance is very wide and in my view this imposes a strain on the knees, particularly on the inside of the knee joint. Another drawback of this wide stance of his is that many frontal movements such as Grasp Bird's Tail and Brush Knee, Twist Step become impractical from the point of view of applications. A quick look, however, at any photo from his books of CMC performing applications, shows that he narrowed the stance for self-defence purposes until the feet were almost in line. A major drawback of CMC's books in my opinion also is that they hardly discuss the appications at all except in appendix chapters. His book on Advanced Tai Chi form instuctions does contain many notes on the applications but these are only accompanied by line drawings of CMC in single postures. This almost complete absence of discussion of applications means that the CMC form is actually not very useful in Chi development, as the mind in the CMC form simply doesn't have any mental imageing of the application to guide the Chi to the appropriate jing points. Another thing that CMC did was smooth out Yang Cheng Fu's postures and in particular, he laid emphasis on what he called the 'Fair Lady's Hand'. This means a flattening of the hand postures compared with the Yang Cheng Fu form and this again is comparatively useless in terms of applications. CMC's reason for the flattening was to assist in Chi flow. However, Chi is like the blood; it can flow round corners and there is really no need to flatten out the postures in T'ai Chi to assist in its circulation.
Cheng Man Ching tried to make T'ai Chi more like Chi Kung with his smoothly contoured form with its relatively closed postures. However, in my view, what resulted was neither T'ai Chi nor Chi Kung, but something that is truly 'neither fish nor fowl' and lacking in the advantages of either Chi Kung or T'ai Chi.
Furthermore, Cheng Man Ching claimed to have spent 10 years as a student of Yang Cheng Fu. Certain scholars of T'ai Chi, have however cast considerable doubt on Cheng Man Ching's claim about that and have pointed out that it is inconsistent with the chronology of CMC's life and that in fact CMC can have spent no more than about a year with Yang Cheng Fu. What is not in doubt is that he assisted in the writing of Yang Cheng Fu's book. But if you look at Louis Swaim's translation and commentary of Yang Cheng Fu's book, it is clear that Cheng Man Ching added some sentences of his own to what Yang Cheng Fu originally dictated and moreover, that these addenda by Cheng Man Ching actually cause more confusion than anything else.
Some Cheng Man Ching postures seem incomprehensible from one who claims to have spent 10 years with Yang Cheng Fu. In particular, the Wave Hands Like Clouds from the CMC form adopts a 'ball hold' position at the end of each step rather than the deflective posture of the Yang Cheng Fu form. However, I have noticed that this seems to be characteristic of practitioners from Taiwan who claim a descendancy from Yang Cheng Fu. Where this interpretation of Wave Hands Like Clouds in Taiwan originally came from, I don't know - but perhaps indeed from Cheng Man Ching himself.
I once corresponded on a Tai Chi group on the web but unknown to me it was full of Cheng Man Ching enthusiasts and when I made what I believed were some rational and polite criticisms of the Cheng Man Ching form, I received some incredibly vicious and offensive replies from adherents of CMC. I was quite staggered in fact, that enthusiasts of T'ai Chi could be so grossly abusive towards a fellow practitioner and this gave me a dismal impression of a Chen Man Ching devotees from the moral and spiritual point of view ... I have also met CMC pracitioners socially and I have noticed a remarkable reverence for him amongst them and they absolutely refuse to entertain any notion that other forms might be equally, if not more, valid. One problem too, is that many CMC practitioners are under the illusion that they possess supernatural self-defence powers. This comes from reading too many Cheng Man Ching books where he makes exaggereated claims about the efficacy of his applications and puts it in the reader's mind that all he or she has to do is execute the application in accordance with CMC's written instructions (in such few places as they actually occur) and opponents will magically fly away at the slightest touch. Nothing is said about the years of practice, hard work, self-criticism etc that are in fact absolutely a sine qua non for even being able to think about doing any such thing as Cheng claims .... Kind regards, Simon.