As a person who has had about 25 years of experience regarding the Chabad Lubavitch I believe that I have both the right and the obligation to share my perspective.
The Lubavitch is a world-wide movement which has created a cult of personality surrounding its late Rebbe, Menachem Mendlesohn Schneersohn. While the Rebbe was dynamic within the movement, due largely to the devotion of his Chasidim, he also attracted less religious Jews, often through proselytizing efforts. But in my opinion the Rebbe attracted less religious Jews, through what has been called the "B'alai Tzuvah" movement (i.e. Jews who "repent and return" to ultra-Orthodox beliefs), by mispresentation. Specifically, he claimed to "love" his fellow Jews and that Chabad had come to the rescue them.
But through my own difficult experience I have sadly concluded that if Jews need love and help there are better off seeking this through other means. Certainly less conditional love would be preferable and there are helping resources available through existing social services and support groups within the mainstream organized Jewish community.
It seems to me that the Chabad has essentially altered both Jewish law and tradition by making performance of the mitzvoth a means of bringing the "messianic redemption," rather than just the performance of a commandment. This is one basis for viewing their movement suspiciously according to more conventional Orthodox groups.
In his lifetime the Rebbe was a tremendous organizer, setting up many outreach centers such as Sabbath Houses, or businesses like pizza stores, which were frequently used for recruitment efforts. Nevertheless, all of this was done for the purpose of bringing some "geulah" or redemption that never happened, and concerning goals that were often vague and nebulous.
Chabad literature has preached that when the redemption arrives Jews will first crown a king, then kill Amalek and finally rebuild the Temple. But I wonder, what would happen if such a redemption was actually realized? What would happen to the rest of us? And what do these people really want? Do they really know?
Chabad literature states that they view themselves as "Torah business people." And they have also said that when a religious Jew talks to a secular Jew, he should realize that he's talking to an "inferior intellect." Thus it often seems that Lubavitchers feel they are doing you a favor by simply associating with you. And subsequently may expect help from others essentially for nothing. The Chabad appears to be ultimately based upon receiving such consideration and charity all the time. But the question is where does charity money go? I am not aware of any detailed financial disclosure, which has been independently audited, published and then distributed upon request. And moreover, does the Chabad Lubavitch ever really reciprocate? Or is charity from supposedly less observant Jews, largely a "one way street"?
During my time within Chabad I met Rabbi Schneersohn twice. Both times he made me feel that I could never be good enough for the movement. Even though I went through hell with my parents due to my commitment, somehow it was never deep enough.
My family came to Chabad originally for help and counseling. But their advice only seemed to make things worse. Upon reflection, we would have been better off seeking out a competent therapist, psychiatrist or social worker. Chabad was not the answer.
While living in the Lubavitch community I was at times both abused and threatened. It seems that the movement contains and often attracts unstable and potentially destructive people.
Id like to touch upon the Chabad outlook regarding the world. The Talmud is quoted in their Tanya (the bible of the Chabad movement) as saying that the "kindness of the nations of the world is but sin." Also they have made statements to the effect that the "body and souls of the nations of the world are derived from the 3 impure klippot (husks or shells), which are evil and contain no good whatsoever."
The Rebbe left no clear guidelines for running the organization after his passing. This was probably due to the fact that he believed that the redemption would take place during his lifetime. Today some within the movement apparently have virtually deified the Rebbe. What many Lubavitchers now believe often seems more like fervent fundamentalist Christianity than Judaism. That is, they are awaiting the resurrection of their "messiah."