I have counted at least 6 brands, maybe more, that are here around Boston. I know ABC and Mandra and one that starts with a C (sorry to be so vague) are all good, but there are a few others as well that taste the same to me as those three. I will try to get you a list of all the good ones, but it may take a while. You might want to do a search on this subject on the forum, as I provided a link at one time to a rosengarden shootout. I didn't agree with his findings, but it is an interesting read. He had a favorite, but my take is that 5 or so of these brands taste exactly the same. I have only found one brand that tasted different, and the problem was that it did not melt right, and was too hard. I often wonder if some of these brands are the same cheese, but just re branded (like we tend to do here in the US).
So far the American versions are all pretty bad as far as I have tasted.
My conclusion about the Italian brands is that you have a five out of 6 chance of getting really good cheese. Unfortunately on the retail level you have about a 2 out of 6 chance of getting it fresh enough to perform well on pizza.
Now, I could be wrong about all this because Marco has just posted that there is a preferred brand that he recommends to his employers, also Jeff Rosengarden had a favorite, but I was doing side by side comparisons on these cheeses when I first discovered the magic of Buffala.