Difference in data products from ESA and Alaska Satellite Facility

I just recently realized that the data products from two different data portals Copernicus Open Hub and Alaska Satellite Facility have different size (difference of almost 300 MB) even though they are the same scene. I am wondering if there is any difference between the data products.

Hi, since the product names are identical, I assume the products are the same and the different is due to the compression used (tar, zip etc). The only way to be sure is to download both products, uncompress and then compare the folder sizes.