While you could debate whether or not this is Buffy's best season, no one can deny that it's the most consistent. This is the year that gave us 'Band Candy,' 'Helpless,' 'The Zeppo,' 'Earshot,' and 'Graduation Day.' I could easily mention another four (or eight or twelve) episodes that rank as classics but, more importantly, this is also the season that gave us Faith and the Mayor. Either one of these villains were enough to carry a season on their own, but their evil father/daughter pairing helped make this season's arc the strongest of the series.
There are a few things about this season that not everyone will love. It gets off to a slow beginning (I think all the bad episodes are on the first disc) and the Angel/Buffy relationship was in full force here. If you liked seeing these two together then you'll love it, if you found them melodramatic then you'll find yourself rolling your eyes. Ultimately, these are small points that don't really detract from the excellence of the season as a whole. Buffy was, fundamentally, a show about growing up and no season captured that better than this one.
The creators really went all out here, giving us four commentary tracks, five featurettes and a slew of interviews. They vary in quality, which is to be expected, but for the most part they're insightful and entertaining. My only gripe is that none of the commentaries are from Whedon himself, but I can forgive that in light of how much content is included.
This is a big step up on season two. The series had a higher production budget this year and it shows, giving us better costumes, more elaborate set-pieces, and just an all-around higher grade of filming. The animated menus of season two are (mercifully) gone.
New fans may want to start with season two in order to appreciate the full emotional weight of what's happening here, but if you're only going to purchase one season of Buffy, this should be it. Latter seasons would grow more ambitious with individual episodes, but none of them delivered a season arc that was this consistently entertaining.