The only thing more obnoxious than invoking the "rise of the graphic novel" in both popularity and "maturity" is complaining about people invoking the graphic novel's rise in popularity and maturity, but real quick: Too many articles and even a few books, latch onto the same group of canonized comics, toss in a few slightly more obscure ones, talk about the Yellow Kid and R. Crumb and Chris Ware and send that ish off to their publisher. Thankfully, Gene Kannenberg Jr.'s 500 Essential Graphic Novels is not another kinda lazy, pseudo-survey of comics, it's a pretty well-done, fairly populist look at a ton of different books.
On sheer volume, Kannenberg beats the "Maus, Frank Miller, Chris Ware" school of "serious" comics writing. There's pretty much no way anybody who opens 500 has read everything within its pages. For a person new or relatively new to comics, the scope of the book and Kannenberg's choices might be overwhelming, but that's a good thing because this is the kind of book that you keep lying around, ready to consult or flip through at any moment. To the more avid comics reader, most (but not all) of these titles will be familiar but Kannenberg's concise but enthusiastic take on one comic or another will make you re-think a comic you hated or remind you of a comic that's been buried in your stack of back issues for years.
Kannenberg also has a way of injecting smart, terse comic criticism into his summaries. He'll often toss in a fairly radical or brave opinion on a certain book in a way that will get the well-informed comics nerd thinking harder, but won't prevent a newer reader from picking it up either. For example, he might be the first person to admit that Mouseguard isn't really that good (but the art and overall feeling of it still makes it great) and suggests that J.M DeMatteis' Moonshadow is the "finest" fantasy comic (and not Sandman). His review of Jimmy Corrigan says that it's "not the masterpiece that some critics claim" which is interesting because it doesn't tow the "comics are smart now" party line and you know, is true. The comment won't stop new readers from picking up the book and gives seasoned readers some food for thought.
If there's a problem with the book, it's that the whole thing feels a little rushed. Again, undoubtedly related to some aspect of the mainstream press wanting to jump on the "comics are cool" bandwagon, Kannenberg for the most part, strikes a balance between making a big, silly list book and adding other layers to it, but some mistakes are egregious. For example, there are a couple of times where the cover image is from a previous printing or is simply a different volume altogether. Not a big deal, but genuinely confusing since Kannenberg goes through the effort of proving ISBNs. His entry on Concrete Volume 1: The Depths is accompanied by a picture of the pretty much out-of-print "The Complete Concrete" (which contains the books that make up "The Depths" and much more), but the ISBN is for "The Depths". Another weird thing is listing 2002's collection of the black and white issues of Madman ("The Oddity Odyssey"), as if the IMAGE collections don't exist (and they came out way before other re-issues that are listed in the book). Does he prefer the black and white issues? It'd be nice to know.
There's also some weird grammatical errors and words missing from sentences, which suggests a lack of proofreading and adds to the relatively rushed feel of the book. This is furthered by the occasional awkward sentence and an unfortunate reliance on cliches when describing a book's effect on the reader. No doubt, a book like this is a balancing act of saying a lot in a little space, not getting too into the minor details, and lots of other stuff, but lines like this, from a description of Farel Dalrymple's Pop Gun War come close to non-sense: "...all of it is well-observed and the story becomes deeply personal for the reader, as well as the writer." How does the story become deeply personal for the writer?
One also gets the sense that for a lot of these, he just dug up one of those really incredible Fantagraphics catalogs from the late 90s that were like, 200 pages and picked and chose weird, lesser known stuff, but again, there's worse offenses than that. These complaints are nitpicking though, because the book's made for people lacking the knowledge to nitpick and again, for those more deeply into comics, what's annoying about the book will bring them back to it over time.