Feels like we need this definition in this discussion.  From m-w.com

ro·man à clef

plural romans à clef \-ˌmäⁿ-(ˌ)zä-\

Sean Blythe wrote: It's hard to argue, at least, that Chabon's heart wasn't in the right place. He clearly loves the stuff.

His heart is in the right place and he clearly loves comics -- I would guess that Chabon's heart is in the right place as far as his writing goes, but not every reader is going to love (or even like) Chabon's writing style.  That's how it is for me -- Chabon has an incredible vocabulary, and he occasionally can turn a phrase that leaps off the page like true poetry . . . but it feels like all too often he's trying to turn a phrase that will leap . . . off . . . the . . . page . . . like true poetry (with all due respects to Bill Shatner).

Kavalier and Clay are not based just on Siegel and Shuster. They are amalgamations of several different comic book creators. The physical description of Clay, for instance, is almost word-for-word the same as a description of Lou Fine that I read in the Will Eisner Quarterly.

When I was reading it I kept noticing points here and there that tied into anecdotes I'd read, descriptions of recognizable persons etc, although often they were tweaked here and there and a couple of different people were put together.

It certainly reads as a roman-a-clef to people who've read or heard of that period in comics history, but there is a degree of fictionalization in that there is not a one-to-one correlation between the characters and real people.

I can't remember enough about the novel to comment on how I would react on reading it now. It's been four years? Five?

It may be important to consider Chabon's THE ESCAPIST

Again, I can't remember how Chabon's story turned out in the collection I read, but it's probably a more accurate representation of how Chabon feels about superheroes than the novel the character derived from.

I don't get that Chabon is obtuse or dense in his article on costumes...he points out, as luminaries such as JB has pointed out, that the superhero costume as it appears in such crystalline perfection in the comic cannot exist in the real world. The material necessary does not exist; the material is at once a language of comics that is inaccessible but to the trained artist, whose imagination, and ours, perceives the Story behind the mask, the cape, or the ankle wings.

I don't think the point of the article is really to comment on costumes, but on the wonder of the comic book world that evidently takes up a huge space inside of Chabon's rather brilliant head. Whether anyone agrees with how he translates that love, is another argument. I can't defend the cat since, at the time I read the novel and the Escapist stories, I was only beginning to get a feel for comics AT ALL after having been estranged for some years. I can't say my views on comics are the same as they were when I was younger, but then not much IS the same. I might have a totally different reaction if I read Chabon's novel now, and frankly I don't want to go over the same ground twice. I've moved on, for good or ill.