On Jack's advice, I reached out to StarBrite.
short answer, the regular products are solvent based, and the "waterproofing" products are water based. Basically pick the one that works for the surface you are protecting...
Full response below:
Hello,
The difference in the two Waterproofing solutions are the solvent that they use. One is a petroleum based and one is going to be a water base, it would all depend on the fabric you are applying it to.
Star brite Waterproofing is compatible with most quality outdoor fabrics including; nylon, canvas, finished leather, and acrylics. However, some economy materials like polyester and urethane-backed fabrics are not compatible with most solvents, so please check the material before use. Also note that solvent-based products can affect the adhesive glue used on some carpeting, and can further depreciate heavily sun damaged fabric. Star brite offers a solvent-free formula, 'Water-Based Waterproofing' as an odorless alternative.