Zobeck Gazetteer or Pirate's Guide to Freeport. But there's clearly a reason for that: those books are 116 and 256 pages, respectively, whereas this one is over 416. And, for that matter, the price compares well with the monumental Ptolus: City by the Spire, which weighs in at 808 pages and $150. (I'm ignoring PDF versions here).
Pavis is billed as the third part of the Sartar line, with the other two parts being Kingdom of Heroes and the Sartar Companion. Like those two books, it is divided between source material and adventures, with about two thirds of the book being taken up by the former. As the third in a line, it isn't intended to be stand-alone, and the nature of Glorantha would probably make it harder to port into other settings than, say, Freeport would be. As such, it's probably fair to say that this is aimed at existing fans, rather than the casual RPG purchaser.
Indeed, that's probably more true with this volume than the previous two, since, it is, of course, an update of the RQ2 supplements Pavis: Threshold to Danger and Big Rubble: the Deadly City from the early 1980s, and has obvious old-timer appeal. The new version is written for HeroQuest 2, although, frankly, that's such a rules-lite system (and most of the setting-specific rules are in Kingdom of Heroes, anyway) that, assuming you're willing to put the work in, the book is almost equally useful to someone playing some version of RuneQuest. Or whatever else your system of choice might be, come to that. (Well, okay, so something like Pathfinder might be a lot of work, but you get the idea).