Greetings. I joined this forum some time ago, but found it unfortunately to limited in it's views with regards to certain aspects of spirituality - now by chance I happen to come back to these pages by way of some google searches and lo and behold; there seems to be some common knowledge about Kriya yoga missing.
i) K (short for Kriya) yoga is approximately 40.000 to 80.000 years old.
ii) It's a secret set of practices (processes, sts) that used to be shared among groups of initiated yogis. Lahiri M and Swami S are among those that have made the techniques more widely known, but most advanced yogis know of certain aspects or similar techniques.
iii) It's true that Yogananda's book does seem to be a little too much of a Hollywood cast story line, btw written with assistance from another person. However, that should not take anything away from him or the LM tradition, but people tend to stick to what they are told and not what they experience.
iv) Without a substantial number of various K traditions, I don't think there would be any point in having the K practices, since they all tend to address a wide variety of various subtle processes.
vi) Practicing K yoga is only one stage in the process of advanced yoga. At one point the more crude K ones should be disregarded, otherwise the advanced practitioner might not be able to live in our modern society, but would only be able to do well in complete or nearly complete isolation.
vi) K techniques cannot be discussed in open forums. They should obviously be taught and learned well, and from then on one should choose carefully as to whether to go deeper in to one tradition or the other.
vii) Even a less 'good' guru/teacher can teach somebody a substantial amount of very deep going techniques that will help that person immensely.
viii) The existence of certain Siddhas can't be denied. Too many people have had experiences at some levels with them in order for them to be void of reality at the finer levels.
ix) Why call them names at all? In the states they are in it's not a matter of what we call them, but of how well we do down here with the wisdom and knowledge they (among others) let us partake of.
x) How would I know? I practiced yoga since childhood, have had experiences of the presence of Siddhas from around the age of 20 as well as have been initiated into K yoga some 33 years ago. I don't practice 'formal' K yoga anymore and I tend to see all the various claims of potentially competing lineages to be made more from a materialistic pov than from a spiritual.
xi) 'God, Christ, Gurus' as Yogananda proclaimed. You can have several teachers, but in the end they are just pointing a finger to the moon; you'll have to do the work yourself to get there and/or just enjoy knowing the moon is there!