Well, they don't really. The mention of Garamond is frequent (to put it mildly) but there isn't a lot of actual endorsement.
Three threads contained actual endorsements of particular Garamonds:
20 Typefaces to start a designer's career
If you could only use 5 typefaces
and the even more stringent
Only One Typeface
The results:
Stempel Garamond - 3 endorsements
Adobe Gramond - 3 endorsements, 1 mention
Garamond - 2
Garamond Pro OTF - 1
And that includes a single person endorsing both Adobe and Stempel.
Now this is an afternoon of combing threads (about 20 or so out of 148 of them), so it looks like I'm at the point of diminishing return.
I'd like to ask some specific questions and see if we can't get a better measure.
Which Garamond
a. Would you buy for your own type library?
b. Would you set a book or long text in?
c. Would you set at display size?
Be specific. Let 'er rip. I'll tally the results in a few days.
Jon