There are other vendors, some in the US. I've ended up with some of this paper and tried it compared to cut-sheet endura. A few caveats come to mind:
1) the paper has a significant amount of curl, and it's usually in the short dimension. It's a bit of a pain to get it to lie flat in the easel.
2) It's Supra endura VC, which is not designed for optical printing, AFAIK. Might be some crossover issues ?
3) the base is not as thick as cut-sheet endura, it feels a little more flimsy, not too bad but not as nice as cut-sheet endura.