The Event: Hosted by Beeradvocate and Dogfish Head, this fest has been going strong for 16 years. It's at the Seaport World Trade Center in Boston, and there are 120+ breweries who join to celebrate "pushing the limits of brewing". 400+ beers, and these breweries are bringing their A game. This year, they also had cider and mead options. You can find something for everyone. It's hard to find a bad drink here, though some of the more extreme ones might be...let's just say 'interesting'. Tons of stouts, IPA's, sours, and everything in between, above, below, and around the side. Another big draw for me is that there's a bunch of breweries that you can't typically get in Boston.
My Experience: I went to the 3rd session, Saturday evening. It was my 2nd year at this fest, and I learned some things from the previous year. The beer list is available in advance, so I looked that up and picked 15-20 that I REALLY wanted, and another 30 or so that I also wanted. I went full nerd, printed out the map and color-coded it so I knew where to go. I managed to try 38 different samples, which is definitely high for me for one of these. I didn't get to all that I REALLY wanted because some of the lines were long, and I prioritized trying more things to waiting in line.
The Beers: The best one I had was Aslin Genius Kitchen (stout), which was about as good as a beer can get. Other beers that were notably good: Benchtop Why The Gong Face (NEIPA), Springdale Elder Mother (sour), Dewey Secret Machine, MadTree Red Eye Chai (tastes like a dirty chai latte), New Holland Raspberry Lemon Kombucha, Throwback BBQ Porter (tastes like BBQ potato chips), Finback BQE Salty Caramel (stout), Weldworks Mexican Medianoche (stout), and Highland Park DDH Losing Control (NEIPA).
Recommendations: You could go a lot of ways with this festival. Some of the most popular stuff runs out in the first 60-90 minutes, but there are so many good options. Definitely make sure to have a water every couple of beers (they do a good job of making water widely available). Also, the inside bathrooms tend to get long lines, but the outdoor ones don't, so don't waste time inside in line. I think one of these 3 methods would be best for beer consumption:
1) Do something similar to me. Make a list of 50-60 beers (more than I did). You can prioritize if you want. Just walk around to different sections of the fest and go to the ones on your list that have manageable lines, and skip the others (unless you need a break).
2) If your priority is specific things, own it, just don't expect to get a ton of them. Wait in the lines right from the start (grab one from a short line first for while you wait), and once all the stuff you want is gone (or you tried it all), explore.
3) Wing it. You will enjoy yourself still and have plenty of good beers. 2 of the ones on my list above weren't even on my initial list.
Expect the last 30-60 minutes to be a giant free-for-all. It's likely half the beers will be gone, so be willing to mix it up.
Finally, this is one of the few fests where it would be totally reasonable to go both Friday and Saturday and not need to try anything twice. If you do that, I'd say commit to getting a few particular beers you want with long lines each day. After Friday, you'll know which ones you missed, so get to those early Saturday.