I hadn't realized there was a unit for measuring bitterness. There is and this beer scores 115 IBU. An India Pale Ale is 40 or higher; an Irish Stout will be 25-60. Wikipedia says the "technical limit" is 100, beyond which there is not much difference in taste.
The beer comes unfiltered and poured quite nicely; it's a pleasant murky peachish-brown. (The label also informed me that the color was 20 EBC.) The head was abundant and cream-colored; it took up about half the glass on my initial pour.
There is not much to the taste of this beer besides sheer bitterness. It's like unsweetened lemon juice, but without any pleasant citrusness. I didn't get any of the fruit aromas or taste that other reviewers mention. "Challenging" would be the polite way of putting it. It did not improve as it warmed.
Other reviews: http://beeradvocate.com/beer/profile/6288/37540
Absolutely the bitterest beer I have ever experienced was a homebrew made by a couple of my college friends. They set out to create the hoppiest beer they could. The result was christened Peter Pucker-Up. (This phrase only has one Google hit at the moment...) It was a dark ale that smelled of skunk when opened. (Beer will sometimes go skunky after getting too much light exposure but this was bad from the very first bottle.) It was drinkable only after having had a warm-up beer (or several) and sat in the fridge as a beer of last resort.