I have been involved in two of the cults mentioned above: Brahma Kumaris and Sahaja Yoga. I have had interaction with TM members too and attended a few Osho meets.
I am very indebted to the BK's because it was through the BK's that I had my first spiritual experiences. At the time I got involved in this organization, I was a hardcore atheist and nihilist. Originally, I got involved in the BK's to learn meditation and because I was directed there by family friends with the promise they will answer all my questions. When I got there the first thing I realised was that this was an outright lie, they do not let you ask questions, but instead ask you to surrender everything you know by visualizing putting all your knowledge inside a box and throwing the box away. Then they proceed to teach you spiritual philosophy and Raja yoga meditation for which you attend once or twice a week the residence of your local teacher for one to one tutorials and group courses, as well as occasional events.
At that time I was not very aware of Yoga, but I soon learned that what they were teaching me was hokey. The first dogma I spotted was when they were teaching me about their eschatology showing me the diagram of the tree with all the religious teachers Krishna, Buddha, Jesus, Mohammed, Guru Nanak, and their founder at the top. They claimed that their leader was the most complete teacher yet and revealed the full truth. When I attended a picnic, I met the teacher of another lodge who told me he burned his degrees when he became a BK teacher, and proceeded to tell me how the BK's had the most complete knowledge by presenting me a dubious analogy of watching a play, some people have been watching the play longer and some have have just come in, the people who were there from the start have the most complete knowledge. I quickly realised this was dogma.
I soon became fed up of how ambigious their meditation technique was. I was told to simply "go up there" meaning to focus on my third eye, while they played a guided meditation tape recorded in a pretentious sounding voice sayomg "I am peace" I soon realised that nobody I met there seemed to radiate peace, in fact the sisters seemed very miserable. I also found the philosophy course juvernile, I was learning no philosophy, but being preached to and soon found my preacher was trying to control my life and if I asked too many questions, they would threaten abandoning me.
When I met one of their success stories a man who they said was a paranoid wreck and drug user in the past, but they transformed him, it was enough to drive me away. Indeed, now he was a manager at boots, but he sounded utterly brainwashed. He told me was celibate, he was learning Hindi because it was going to be the language of the world in the coming golden age, and the whole world will perish, except India. Nothing he said convinced me I was speaking to an independent person. He sounded like a robot.
The final nail in the coffin was when tedium set in with the group meetings. I realised there were people coming there for years to listen to the same damn lectures every week. They all had a very brainwashed quality about them. I asked them what was the need to repeat the same lectures every week, and they told me repetition was needed to install the teachings. But for years? I knew I was not going to develop with the BK's, so I simply stopped going. Occasionally they invite myself and my family to events and we attend out of courtesy, but none of us go to their weekly classes.
Now, a lot more knowledgeable, I realis the BK's were a highly dubious and watered down version of real Yoga. They did not teach Raja Yoga at all, but some new-age stuff that they called Raja Yoga. They falsely advertise that they teach Raja Yoga. They are relatively harmless though, the only flaws I could see was that they were naive and gullible and did false advertising, but I saw no evidence of foul play.
I was involved in Sahaja Yoga only very recently, about just over a year ago. Initially, every cult I have attended seemed positive, and my experience was the same with SY. I saw them conducting a public worshop at our local mall and was impressed with all the energy work they did. I liked the sound of a Yoga that do energy work. But within 2 weeks I realised it was too good to be true. I became acquainted with their pseudoscience of checking vibrations and soon realised they used this pseudoscience to push their organizational dogmas. Basically whatever they believed they said I could check by "checking the vibrations" while tacitly telling me not to question anything. I quickly clocked that they worshipped the founder as the divine mother, but I decided to overlook that so I can learn the energy work. When I did eventually, I realised what a pile of made up crock it was. It was based on very subtle sensations on your fingers, even something as basic as feeling an air current, and based on that a diagnosis was made of which chakras were acting up. If you could not feel the vibrations, that was fine, because they would confirm it for you(wink) But I made friends there now and we did things together, so I stayed for a while. But when they took me to a going deeper meeting and showed me a brainwashing video of their founder it repulsed me. I soon got in touch with them and told them I had ideological problems with their claims about their founder and told them I would be leaving. They responded, "That I would eventually find out their founder was really the divine mother, but I did not know it because I could not check the vibrations"
Needless to say, I left and so did 3 other people I introduced to it. I guess none of us were feeling the vibrations from her divine holiness