If I remember rightly this was stocked in the Gower St Waterstones under "Essays". In fact the first item (Monkeyhouse) is almost entirely made up of stories (the first bit is a bit of Sunday mag journalism, Vonnegut-styled), while the other, Palm Sunday, seems to be a collection of speeches made to churches, universities, clubs etc, stitched together fairly loosely.
So first off, it wasn't what I was expecting.
I dutifully read the first few items in WTTMH. These were well enough made and charming enough if you like that sort of thing. I don't, though I did my best.
Then I skipped forward to PS. This was a bit more promising, as KV discussed real subjects; but in the end I had to semi-skim this too.
His stories are wacky and "imaginative" in setting; fairly traditional in narrative construction and indeed content; and above all folksy and moralising under their thin decoration of novelty.
I'm sure he was a reasonably nice guy. Of course one doesn't (well I don't) read a writer for their real-life charmingness or decency, but for their skill in entertaining or provoking thought (their may be other relevant skills but I can't think of any offhand).
I reckon I'd see eye to eye with Kurt on many things. But he rarely provokes (or, apparently, engages in) thought and he entertains only very slightly. He has a low-key but insistent and grating sentimentalism. Also, he mostly seems unnecessarily pleased with himself. He has a pseudo-humble persona but one which always insinuates (fairly unmissably) something like "ok, Mister bigshot/ bad guy / whoever, you think you're pretty smart, but really little ol' Kurt with his simple ways is maybe better'n you after all. Hmm?"
Example: he prints in PS an introduction he'd written to an edition of Swift's "Gulliver's Travels" (yep, Swift's one, not those other ones) - prefacing its chapter by announcing that, despite his eminence (pseudo-self-deprecation), the publisher had rejected it on the grounds that, in KV's words, he "had sentimentalized Swift, having failed, apparently, to have read any detailed accounts of his life and character." The rejected text follows immediately, and entirely bears out the publisher's objection.
Not my cup of tea.