Although most well-known pop gurus are from, popularisers of, or initiated into, the Hindu Vedantic tradition - so-called NeoVedanta - not all pop gurus are. There are many in the West who come from a Buddhist, most especially a Tibetan Buddhist, background.
The influence of Tibetan Buddhism on the current wave of the New Age movement, influenced as it is by Wilberian and New Paradigm memes, cannot be under-estimated. It is probably equivalent to the influence of the first wave of Hindu gurus during the 60s and 70s.
My knowledge and direct experience with Tibetan Buddhism is pretty limited, and so in these pages I will be relying mostly on the perpsective provided by a friend who has delved into these subjects rather more than I have.
My own experience, derives from a Tibetan Buddhist group whose talks I went to here in Melbourne many many years ago. I found them really lovely people; there was the Geshe, the translator (who I got on really well with especially; a delightful man, he later gave up his vows for the life as a householder), and a whole bunch of Western devotees.
Because of my positive experiences with them personally, i always thought highly of Tibetan Buddhism, even though i have never been attracted to that path. I found the teachings to be very restructive, formalised, overdetailed, religious, and quite exoteric in approach. Of course these were only the beginner classes; but i was never motivated to get initiated and get into the more esoteric practices, which were no doubt just as literalist. The similarity with Judaic Kabbalah, in which a wealth of esoteric knowledge is available, but must be extracted from the huge overburden of literalism and religionism, is quite intriguing. No doubt one can also make parallels with Sufism, Fourth Way, and many other teachings too.
A friend has compared getting involved in Tibetan Buddhism with getting involved in Catholicism.
A correspondent suggests that some people who were attracted to Tibetan Buddhism were so because they idealised lamas as magic figures and then came to grief because of these unrealistic expecations. Another source of misinformation here would be through reading Carlos Castaneda's books, and assuming his books were a truthful guide for spiritual practice and what to expect to get from it.
A more recent source of appeal for Tibetan Buddhism is via the teachings of Ken Wilber. Wilber has a Tibetan Buddhist teacher or teachers, which raises a whole subject in itself
Then there are the abusive gurus within the Tibetan tradtion (one or two of which are also Wilber's teachers), such as Chögyam Trungpa and Ösel Tendzin
Of course not all Tibetan Buddhists are like that. Those I knew certainly weren't. Also there are teachers like the Dalai Lama. Sometimes an allegation is made, as in a legal case against Sogyal Rinpoche, but I would be highly sceptical of taking one isolated allegation as proof that the guru is fake. But it is that the tradition itself doesn't provide any immunity from this sort of thing. Just as there are some people who are Christians and they are the most spiritual people. But they are spiritual because of what is within them, not because they are Christians. Sure the Christianity inspires them and helps them to contact their Inner Light, but it isn't the cause of that awakening; only an instrument their soul uses. It is the same here.