Our watermaker feed hose is black reinforced rubber Trident 100 series and we have experienced no problem or taste issues for the past 5 years it has been installed.
I agree with you about questioning clear vinyl braided hose below the waterline. There are different grades and thicknesses of this hose and I would only trust the higher grade, thicker hose below the waterline. The stuff sold in West Marine
and most other chandleries is the lower quality, thinner stuff. I have experienced scary issues with this below the waterline.
The Trident stuff is top-notch for below waterline use and is all I use now after some failures of clear braided vinyl.