I am not familiar with this product, but I would think that you would also want to use their floor stain (for compatability reasons). Based on a quick glance at their web site (Vermont Natural stain colors), it did not look like they offered a lot of choices. Most of the options seemed lighter in color.

I mention this only in case you wanted to go darker than what they offer.

I’m wrestling with the same question! We just put in reclaimed fir flooring and I’m leaning towards PolyWhey and other low-VOC options, but spouse and contractor are pushing for oil-based poly bc of durability, primarily water damage concerns. I’m very curious to hear about others’ experience with PolyWhey.

I've used some PolyWhey in years past without issue. Is it the longest lasting or hardest wearing? Probably not, but do you need the ultimate in durability? Consider that once your floor wears and gets scuffed up, it should be abraded and recoated periodically. People who keep a nice home generally don't wait until it wears out before recoating.

Consider that for many, many years, the only non-yellowing waterborne finish we could use on white floors was Bona's second cheapest product, yet it didn't cause durability complaints.

OTOH, if you currently have issues with your floor wearing significantly, you should go with a more durable finish. For example, I refinished a floor for a GC in his own home where the floor wore rapidly due to a sandy environment, kids and dogs. Using a high durable moisture cured urethane solved the wear problem.