The potential answers to that question can literally fill a text book. Manufacturers generally do not rename the same coverstock; occassionally, sister or subsidiary companies use a different name for the same chemical formulation.

It is almost impossible to do a true comparison of coverstocks because you cannot put the same core inside different coverstocks. Core are also proprietary to each company, although that idea would be extremely educational.

I let better minds (and typists) do any comparisons. (I would be here all day and never get any Christmas work done.)
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"Just because you can do something does not mean you should do it."