It was during a couple of visits to Drepung back in 1990 and '91 that I got to know Tsem, or "Tenzin Sopa" as I knew him then. During that time, Tsem didn't attend any philosophical classes. He didn't debate, and AFAIK, he didn't complete any exams. Not even the "Du-dra" (Collected Topics) class, which is the first year in the 20 or so years of the Gelugpa examination process. So you can draw your own conclusions about the extent of his knowledge of Gelugpa philosophy. I heard that he had a Bhutanese ID card, which allowed him to live in India without visa problems.
He seems to have spent his first few years (of a total of 8 spent at Ganden) befriending various lamas with the aim of trying to get someone to "recognise" him. When none were forthcoming, and the medium for the Gaden oracle was retiring, he tried to get that position. Unsuccessfully, of course. But it is consistent with his strategy of trying to get some sort of title without really earning it. Becoming a geshe probably didn't atttract him because it would have been too much work and would have taken too long.
One of his good friends was Gomang's Lobsang Yeshe, unrecognised claimant to the title of Kundeling Rinpoche, <SNIP>. Neither did any study, and both spoke English better than they did Tibetan. They used to spend their days being served tea by Lobsang Yeshe's attendant and trying to think up ways to become the next Lama Yeshe or Zopa Rinpoche. While Lobsang Yeshe at least had an unrecognised claim to being a lama and had completed 6 or 7 years of the geshe curriculum, Tenzin Sopa didn't have any title. But it was fairly obviously something that he craved.
Even at that stage, he had a story to tell, though my take on him at the time was that he was an unwanted, unloved and unhappy child who had found solace in Buddhism. But he was never satisfied with being an ordinary Buddhist. In his own personal sense-making life narrative, he was special. Perhaps imagining himself as a reincarnate lama may have been a mechanism to show everybody who had mistreated him that they had been making a big mistake. The fact that he had been suicidal (he once told me how he wanted to kill himself so that he could come back and start life over again) suggests to me that he was not entirely balanced mentally.
Eventually, practical exigencies seemed to have prevailed, with the powers-that-be in Shartse college seeing the advantages of having a fluent English speaking lama for raising money for the college and attracting sponsors for individual monks. I don't know anything about the teacher who recognised him as the reincarnation of a former abbot of the college. I don't know what authority he had to recognise incarnations. I don't know of any other monks that were also recognised by him. (It would be interesting if Tsem was the only one, and whether the teacher benefited personally from the recognition.) Nor do I know on what basis he was actually recognised. (Did he correctly select possessions of the former abbot?) These are questions to which those who currently follow him are entitled to know the answers. But perhaps it's beside the point--the main thing is that Shartse College issued him with some sort of official document recognizing the recognition, and the rest is history.
Some of the young monks at Drepung used to refer to him as "Lama Dzuma" ("fake lama").
That said, since then I have had nothing to do with Tsem, and I have no personal beef against him. He once did me a favour for which I was very appreciative at the time. AFAIK, he observes the monk's vinaya purely and therefore at least deserves the basic respect accorded to any Buddhist monk.
I have also been informed that the following website--which pointedly avoids proper names, presumably out of fear of legal retaliation--is really about Tsem's organization, Kechara:
It seems that the Kechara organization is suffering quite a few defections right now, not least because of Tsem's famously mercurial and tempermental personality. You may choose to interpret his mind-games as "crazy wisdom," but these allegations deserve to be more widely known. For example, the above blog depicts its unnamed "chairman" as a cult leader who spies on, manipulates, and physically abuses his own followers. It also seems that there has been a wave of high-level defections lately, and that the ex-Kecharians are starting to organize themselves.