Solvent protectors used to have two key advantages.
1) With no water you did not have to worry about sensitive fibers bleeding or shrinking.
2) Solvent would dry faster than water.
These advantages are being lost as more and more states regulate what solvents can be in the protectors. To get lower VOCs to meet stricter regulation, the product has to evaporate slower. Some solvents do not dry any faster than water, now.
Bridgepoint Maxim with Dye-Loc has removed concerns about the rare fabric that may bleed. With proper low moisture upholstery tools, shrinkage is rarely an issue any more.
Bridgepoint still makes Maxim solvent based protectors, but I suggest many cleaners would prefer the water-based Maxim with Dye-Loc if they tried it.