How can I compare different Greek Grammars?
I'm thinking, maybe look at them. TOC's, basic vs advanced, and so forth. Or an appreciated author ... that'd be Jouon and his ever so careful wife.
But for me, I use a CitedBy of grammars for automated comments.
Good idea, but that'll likely favor reference grammars. She's also right, though: Look at them, look at the TOC, and determine what kind of grammar you want.
Open Factbook. Type in the Greek grammatical thingie you're interested in (e.g, "Genitive Absolute"). (See image below)
Alternately, open the resource "Faithlife Greek Grammar Ontology"* and view the hierarchy (via TOC pane) to get where you'd like to go.
This assumes you've got a Logos 9 package that includes the Faithlife Greek Grammar Ontology.