The folks at Cornell have done a marvelous job with this critical edition. Puttenham is chock full of obscure references, archaic language, and polylinguistic quotations. All of these are carefully navigated with an assortment of notes and a lengthy introduction (which is more entertaining than it has any right to be.)
As for Puttenham's text itself, the first two volumes are much more interesting than the third--which is essentially a long list of rhetorical figures, interesting only for the many verse quotations (often from lost manuscripts) and Puttenham's occasional parables, some of which are witty, most of which are dull. Readers looking for an Art of English Poetry from the era would probably be better off with Sir Philip Sidney's Defense. But if you're crazy enough, Puttenham is a neat curiosity.