This book contains every PA comic from 2005. That wasn't a bad year for PA, so you're getting good comics... all of which are still perfectly available online. To me, the only point of these volumes is to have a physical copy to read while "dropping the Cosby kids off at the pool." Here's the thing: The first five PA volumes were published by Dark Horse. This sixth volume was published by Del Rey/Ballantine, and some changes have been made... and not for the better.
Until now, I never really gave too much thought to the books themselves; they're just typical comic paperbacks. But now that they've changed publishers, the drop in quality is instantly noticeable. The paper stock is lighter/cheaper than previous volumes, particularly the cover. Volumes 1-5 all had printed inner covers, they were covered by gray-scale patterns in keeping with the theme of each volume (e.g. the inner cover of Birds Are Weird was printed with a pattern of pigeons.) I never even noticed that before, but I notice now that I'm looking at vol. 6, which has blank white inner covers. They've used a weird new font for the titles of the strips, which is mildly annoying. In previous volumes, Holkins' commentary for each strip was always, ALWAYS directly beneath the strip he was commenting on. In this volume, sometimes the page layouts are such that there's no room for the commentary below, so they put it on the opposite page instead; seems kinda sloppy. (Though the commentary is as fun to read as ever, usually... a few of them do seem a bit "phoned in".) Moreover, vols. 1-5 all shared a common graphic design philosophy whereby at a glance it was obvious that they all belonged to the same series. Vol. 6 has a completely new design style, so if you put them all on the shelf together, suddenly there's an odd man out. Mildly annoying.
To sum up: Great comics, great commentary, mildly annoying drop in production quality, series consistency has been chucked out the window. On the bright side, at least now I have a new appreciation for how well vols. 1-5 were put together.