My feeling is these books get less inventive and funny as they progress (some of the jokes in the last volume are pretty flat), but they become ~deeper~ instead. O'Malley may have always intended to cut his hero down to size, or he may have experienced a slow dawning realisation as the books found an ever-growing audience that Scott may not be the best person ever. But if reversing that impression is bought at the expense of a few wisecracks and some wild formal experimentation, I think it's a fair trade.
I had two misgivings when I read the first four volumes. Number one is that the portrayal of certain non-white, non-straight characters was caricatured and potentially offensive and alienating for some readers. True, we are always looking at everything through Scott's less-than-perfect gaze, so those portrayals may say more about Scott than anyone else. However: he remains the hero, and it's therefore too easy to become complicit in his unthinking attitude to the people around him, who are too often treated as joke-fodder rather than as people (in ponce: 'means' rather than 'ends-in-themselves').
Misgiving number two was that for someone reared on Buffy and with the expectation that the fantastical elements of a fictional world can be read metaphorically in some way, I found Scott's showdowns with Ramona's evil ex-boyfriends difficult to get a handle on. Especially as the exes were about as three-dimensional as the Gym Leaders in Pokémon. In fact, Scott's drama with his own ex-girlfriends took up far more space in the books, while Ramona's character remains difficult to figure out. She is the cool, American ('othered') femme fatale Scott is gunning down all the bad guys for, but her exes don't really shed any light on her history. Instead it's Scott's history we're working through, slowly exorcising past relationships on the journey to making the new one work.
Both of these misgivings – Scott's profound dumbassery and the fundamental metaphorical instability in the book – are to some degree worked out by meeting Scott's nemesis Gideon, the last evil ex-boyfriend. Because here the final boss (a bit like Ash's rival in Pokémon) does cast light on Scott's own character. Gideon flaw is that, like Scott in much of the book, he treats everyone as a means to his own ends. The most powerful moment in the book is a double page spread where Scott flashes back to moments he has been dumped and corresponding moments when he has done the dumping. He (finally!) puts himself in someone else's shoes. And that earns him the "power of understanding" that allows him to defeat Gideon.
That may sound a bit thin, and I would understand if some readers are not ready to forgive Scott's sins just because he learns so basic an ethical principle (when he's 24!). But I still like the book for the way it tries to deal with my second misgiving – the final boss adds an interesting metaphor to (some of) the fantastical elements that appear in previous books.
Ramona's head glows when she walls off her problems and refuses to communicate. We learn that Gideon has 'infected' her with this condition, and in fact her response to it has been to tunnel inwards and escape situations she finds impossible to deal with (hence her ability to enter hyperspace and teleport). Ramona is not as self-involved as Scott, but both of them are liable to run away from (or in Scott's case, willfully forget) their baggage.
What's intriguing to me (and I accept that I may be reading a bit into the text here) is that Gideon creates his virus as an entertainment industry arsehole. He embodies the worst aspects of the means-over-ends business, and you can take this in an anti-capitalist direction if you want. For me though the inference is more specific. A book so saturated in video games, manga and pop music nevertheless has within it an underlying worry about our ability to connect with other people, and perhaps a sense that these super-fun distracting things can be part of the problem.