We use Red River paper for our large format print lab at our university
The Polar Matte paper and Ultra Pro Satin papers have far surpassed our old selection of Epson paper for student and faculty work. The Polar Matte is a beautiful surface, smooth and white making gorgeous prints on the Epson printers. The Ultra Pro Satin is the new paper out by RR and makes rich prints on both the Epson printers and also the Canon Pro-1 printers. The Canon printers do not do well with any of the matte papers we use since they are not fine art paper. (The only time Canon Pros use matte black ink is when they print on the matte FINE ART PAPER USING THAT SETTING. When they print on the Polar Matte, they use Photo Black ink.)
I have been a Red River paper user for many years and got our lab to change papers for better looking prints. Everyone has been happy with how good things look now.