I have used KASL with a Lehmann recipe for about two years now with great results. I make pizza once a week. Recently I was unable to get KASL and got a bag of All Trumps and was very disappointed. After several attempts to tweak the recipe for the AT I was getting dough with the right consistancy but the taste, the color, and the texture were all inferior to pizza made with KASL. The AT did however make excellent pretzles, but thats for another forum.
I have found that trying to buy a 50 pound bag of KASL is a challenge. There are many places in New England that sell it but not to the public, only to businesses. I do have two retail sources for anyone looking in New England though.
Perkins Marketplace in Middleboro, MA (508) 947-8211
King Arthur Flour Retail Store in Nowrich, VT (800) 827-6836
Prices run between $25.00 and $30.00 for a 50 pound bag. Call ahead because surprisingly neither one has it in stock every day.