Wow, you guys are lucky (I think) -- I am only going to try Grande's 50/50 for the first time in a week or two. But I am out West in Seattle and the only place I can get it only carries the 50/50, not the East Coast Blend. I wish I could try both side by side.
Over the years I've used a variety of mozzarella cheeses, from Tenuta's 5# low moisture part skim loaf/brick (a Kenosha, WI cheese), to the usual store varieties, including Costco, and I tried "First Street" (both whole milk and "pizza cheese" blends.) Frankly, the First Street didn't knock my socks off. But I'll definitely let you know how I think the 50/50 stacks up. I do have high expectations, as many people say good things about Grande's products here on this forum.
I also have a question: how many of the Chicago-area pizza places do you think use Grande products? Any sense? Just curious where its biggest markets are, because there's not a lot in Seattle, I can tell you that. if anyone has good Seattle recommendations, please le me know!