I stumbled upon this festival quite randomly while venturing out in search of a bite to eat. The…read morefestival stretches for about a mile along Karl-Marx-Allee in Friedrichshain.
The crowds were well-behaved in the early afternoon, and the festival was clean and well-organized. There were tons of trash cans but not enough recycling bins, which was a problem because it took a bit of hunting around to find a place to deposit an empty bottle. There was ample seating, a few stages with reasonably entertaining musical acts, and ample available portapotties.
I tried small samples of three beers (about .2L of each) and didn't end up finding any I liked, which is strange because I really enjoy beer. I also noticed that many of the beers here were brands that you could find anywhere in Berlin at any time, like Weihenstephaner, Köstritzer (which is delicious, but still), and so on. However there were a few more unusual options like Ghanaian beers brewed with mango or banana, Guinness bottled for the African market, and, available from a Scottish vendor, beer brewed with seaweed. So you can get a bit more adventurous if you like.
I did not wish to drink very much but if you want to sample a lot of beers, you can buy the festival "Probierkrug" which is a .2L mug, and the folks at the beer stands will pour out small tasting portions into that mug.
But what I was mostly looking for was something tasty to eat that I didn't have to prepare myself. I tried some Dutch poffertjes for the first time--they are like silver dollar pancakes, and they were served with powdered sugar and orange liqueur poured over top. I also had a venison bratwurst, which was quite good although not very distinct in flavor from its porcine counterpart. For my husband, I procured a ham sandwich (the ham was moist, delicately smoked, and not overly salty) and a burger (125g of well-done beef with ham, sundried tomatoes, red onions, dill pickles, and lettuce on a rye bun). He enjoyed both of the sandwiches very much. So oddly enough, I would sooner recommend this festival for the food options than for the liquid ones.
The festival is definitely not worth making a special trip to Berlin for, but that being said I could think of far worse ways to spend an afternoon if you are here in the city and I do think it was well done.