Small But Vicious Dog, his juicy hybrid of Warhammer Fantasy Role-Play (the old version) and Basic/Expert D&D. Especially if you are a fan of the lowlife end of adventuring as expressed in things like the 0-level "funnel" of the DCC rpg or Johnny Nexus's tales of Fat Gregor.
There's a lot of good stuff back into those 36 pages of Hogan's, but I just want to highlight two things. First, the text is really funny. It's just a hoot to read. Hogan really nails the cynical black humor of the Black Adder vein.
The other thing he does is borrows from elsewhere cite his influences right in the text. For example, Jim Raggi has one of the sanest methods for adjudicating encumbrance, so borrowing his rules makes a lot of sense to me. Mr. Hogan does exactly that, and says so right in the encumbrance section. I like that a lot. The kind of folks who write up D&D variants should be swiping each others' best bits. Because really, unless encumbrance is your bag, finding someone else who has already put the work in is a godsend. Ditto any other type of rule that you aren't inspired to work over yourself.
I've seen quite a few published 3rd party books for 3.x that borrowed open content from other publishers, exactly as allowed under the licensing. But sometimes the only way you'd find out that part of the book was someone else's work was by reading the stupid tiny-fonted legalese in the back. That sucks. If someone is good enough to swipe from, don't hide it under a bushel. There's no need to be insecure about borrowing, especially here in the OSR scene. We already rely on ridiculous amounts of material from Gygax and Arneson and many others.