Grande's 50/50 blend is half part-skim mozzarella and half provolone (their version is called Provonello). The blend was devised for mid-western pizza markets and some New England markets that heavily blend mozzarella and provolone on all of their pies. Grande blends part skim with provolone because the provolone already has such a high fat content that oil off and burn can be a problem. Those characteristics are diminished with part-skim mozzarella. However, the blend still can have some burning and oil problems depending upon how the pies are prepared. I would avoid using this blend in a high temperature situation--anything over 550-600 degrees or it will surely burn.
Grande's whole milk mozzarella performs beautifully in all applications, even in the highest heat, it still melts great without burning. Also age plays a great roll on how this cheese performs. Some prefer "newer" cheese because it is a bit less salty and is a bit milder in flavor. Others will only use "aged" which is over a month past the date on the loaf or package. I am one of those who prefer to have a bit of age on their product. The cheese takes on a more developed nutty flavor as it ages and along with that a more pronounced flavor of salt. Think of the difference between any fresher cheese and aged--the aged loses moisture and concentrates the flavors and the salt. Since I don't add any salt in my sauce and the other toppings are salty enough, I like the flavor that aged Grande brings to my pizzas.
I understand that it is difficult for consumers to get Grande, let alone control the age of the batch--but that is why some of you report different characteristics from the cheese--it does change as it ages. Some places actually specify a certain number of weeks age on all the Grande they buy. I like at least 6 weeks age--6 to 8 weeks is optimum for me. There should be a batch number and date on each loaf or package.
PS: Part skim should not be aged; use it as soon as possible, or freeze it. Unlike whole milk, it develops mostly a salty flavor and because of the reduced fat, it does not develop a richer flavor like the whole milk version. I also find it tends to dry out faster.