The website seems easy to understand, I like that. Something that's a bit unclear to me is how will I pay? It costs money, but nevertheless "There's no sign-up or hassle for either of you" ?
Another thing that comes to my mind — what about privacy? I don't know who you are. Likely there's something important in the file that I don't want unknown people to have access too. — Google Drive feels safer in this regard, feels as if I know who Google "is" and it doesn't have any interest in looking inside my large files.
How large files b.t.w.? 1 GB? 1 TB?
If you want feedback from more people, you can try https://usability.testing.exchange (I'm developing it).