I stand by the idea that codec doesn't matter, at least not enough to worry about.
If you have the bandwidth and storage, go ProRes. If you want to be more conservative, go H.264. All agencies take either for 4K (except iStock - they don't take H.264 unless in a MOV wrapper). And Videoblocks won't take H.264 for HD at all.
You sales won't be affected in the slightest. If you have the content the buyer wants, they'll never give the codec a second look.