What you are looking for is called a stone sealer; a sealant seals joints between materials.

Stone sealers usually consist of fluoro-carbons, fluoro-Teflon, acrylic polymers, etc. A google search for HydroShield granite sealer reveals that it is a solvent-based flouropolymer. I doubt that it is any better than the other sealers.

Sealers only reduce the rate of absorption of a stone and that allows more time to clean up a spill. If you have chosen a light porous stone for a kitchen you will probably have to clean up more quickly and reseal it every 2 or 3 years. Denser dark granites don't usually need a sealer.

I would pay no attention to the warranty. It probably gives you a rebate or another bottle of the stuff that failed if you are willing to go through the hassle of proving a claim. It's offered only for the advertising value.

Online reviews are worthless unless there are so many that the company could not have written them all. Assume the best reviews are from them. These people are trying to sell a common chemical directly via the internet to homeowners in a crowded marketplace. Buyer beware.

Ask the company that installed your counter for a recommendation. If they didn't warn you of this problem they owe you.

I don't see any reviews at all, good, bad, fake or otherwise.
There are not dealers in every state and they require professional application, so it is not a widely known product. The warranty says that if the coated granite surface stains within the five year period, they would either refund your purchase cost or recoat the surface at their expense. Right now, I cannot even go 5 months between reapplication of the current granite sealer. If I only had to reapply every 2 or 3 years, then I wouldn't be looking at this, but reapplying every 3 months for the last 4 years is way too much work and makes me really regret getting granite in the kitchen and bathrooms.

The company that installed the counters went out of business a few months after the installation.

Hydro Shield is NOT your everyday over the counter granite sealer. Most of those products are what is called a penetrating sealer that "soak" into the granite and protect under the surface. Hydro Shield Penetrates but also chemically bonds to surfaces at the molecular level eliminating microscopic peaks and valleys where corrosion and stains begin. This causes the liquid to sit on the surface with a higher contact angle. The Hydro Shield warranty is backed by your local authorized installer with a true warranty. Hydro Shield has been tested to last up to 15 years on Granite. Hydro Shield is opening new areas all the time. Hopefully someone in your area becomes a licensee soon. The product REALLY works! I personally have not found another sealer that works as good or better.

so did you use Hydroshield?

I have a business card for a Frank Freda, owner of Hydro Shield of Somerset Hills, NJ. Haven't called yet.

I suspect for a tricky material like granite, a fancy sealant is worth the money. Has anyone used Hydro Shield on glass shower walls or plain old grout? Probably sticks to grout (cement) fine, but in my experience nothing sticks to glass for long, judging from many years of applying Rain-X to my car windshield!