Best is subjective. My favorites are from Treehouse, Trillium, Foley Brothers and Hill Farmstead. Best readily available? I think that depends on your location. In NY? Probably those I mention below.
NY makes some good ones. Other Half in Brooklyn is great but hard to get, Singlecut in Queens (Softly Spoken Magic Spells is the best and most NE IPA like in my opinion), Grimm Artisanal Ales, Finback makes several good ones, and some others. NY has really stepped up. I happen to think Captain Lawrence is not one of them. Some may argue.
Top Rated Beers: New York (US)