I've actually come across a number of people who shit talk the man, saying his notes are shoddy at best and the experience notes given do very little if nothing to characterize the drugs. All the way to statements of him stealing ideas from Nichols and so on.
Oh boy. I'd love to have a few minutes to 'debate' that point with anybody foolish enough to rattle on like that.
The point isn't that they're wrong because the Shulgins somehow trump all other psychedelic researchers. Rather, they're wrong because its not either/or. This goes to a larger point about culture and design: nothing is invented, improved upon, or explored in a vacuum. There is always background, the larger picture of what's going on, give and take, and so forth.
It's undisputed that Nichols first synthesized some of the compounds in either of the XIKaL books. He also developed some of the techniques that were used, exhibit A being the method of resolving the enantiomers of the psychedelic amphetamines. But that doesn't add up to beef between Sasha and Nichols, that's silly, and proposing such an idea is also silly, not to mention counterproductive.
The truth of the matter as I see it is that the two of them do not do the same thing. There's no question that Nichols is one of the foremost authorities on the mechanistic workings of our neurons as relating to the various serotonin receptors. For various reasons I believe I understand, he has chosen not to widely publicize any personal use of psychedelic compounds in the manner Shulgin did. Conversely, Shulgin is likely our foremost authority on the extraordinary variety of altered states that are possible. The important thing here is that he did it in a manner that attempts to submit a completely qualitative, messy, deeply personal experience to scientific scrutiny. Sometimes he did that better than others.
To the average psychedelic drug user, Shulgin is probably more practically relevant, because his compiled experiences and the experiences of his coterie of friends and fellow research subjects allow people unfamiliar with psychedelics to at least know very generally what to expect. And certainly for us chemists, 'synthetic diddlers' in his words, the concise, reliable procedures in his books are literally invaluable. In the study of the underlying mechanisms of psychedelic states, Nichols is already and will be remembered as being more important in that area of research.
I think that I'd anybody wants to argue that the 'qualitative effects' comments in either book are 'not helpful', they're being deliberately obtuse, and furthermore have likely confined themselves to the free, online portions of Shulgin's writings. The dude could use our help, I'd suggest that whosoever makes spurious arguments like these ought to pend a tiny bit of money and buy a copy for the guts of his writings that aren't posted for free on erowid, and reserve their judgement until then.