I'm an occasional whodunnit reader, and this was my first Rex Stout book. I wasn't terribly impressed.
A few amusing vignettes, granted, but the writing (apart from literally one or two good lines) was middling at best, and the plot was hardly original or surprising -- although perhaps Madeline Fraser's secret would have been much more shocking in 1948 than it is today.
But the worst thing about this book was Wolfe himself. I just didn't find him convincing at all. (The other characters, though, were much more so, especially Archie, who admittedly was the narrator, which must work in his favour believability-wise.)
That's the problem with eccentic geniuses, I guess. You need to be a very good writer to pull them off. And Stout just ain't quite there. (Conan Doyle, whose Holmes & Watson Stout's Wolfe and Goodwin seem to be poor imitations of, was more successful with his great detective. Holmes, though equally eccentric, was somehow always palpably real. The character of Nero Wolfe, on the other hand, just seems artificial and contrived.)
That said, the episodes with Nancylee were funny. And the glimpses of the big-money sponsors' machinations were quite diverting too. Same goes for Archie and the way he reveals to the reader his frustrations with the "genius" Wolfe. It's just a shame the supporting characters are so much more compelling than the central one.