Heady Topper is the one and only beer produced by the Alchemist Cannery in Waterbury, VT. I can honestly say that Heady Topper is the best tasting beer I've ever had. And I've had many beers. I've actually had many Heady Toppers, so it's not like I tried it once and am glorifying the experience.
Many other beer lovers have reached the same conclusion, as it stands at #1 on top beers list as rated by beer advocate users.
http://beeradvocate.com/lists/topHeady is only available at the brewery in Waterbury and nearby (like within 30 miles) stores and restaurants. Numerous beer geeks drive to Vermont, buy it by the case, bring it home and share with their friends and/or trade with other beer lovers around the world.
Because of it's lack of distribution, Heady is a much tougher find than Hopslam. Hopslam comes out once a year, and you can usually get plenty of it for a week or two in January, as long as you reside in a state where Bell's distributes. Heady IS produced year round, but again, you have to drive to the source, trade, or have a good friend in order to acquire it.
In terms of taste Hopslam vs. Heady, Heady wins by a mile imo. Also, Heady retails at $3 for a 16 oz can whereas Hopslam works out to something slightly higher than that per 12 oz bottle.
The only downside about drinking Heady is that when you run out, anything other hoppy beer is going to be disappointing by comparison.
Pardon my complete ignorance on the topic, but what exactly is the big deal about this Heady Topper beer? Is it basically just another company's Hopslam (in both hoppy-ness and low availability)?