Although I was late to the party on researching granite sealers, I always knew sealing was a necessary step in order to protect the slabs from stains. The traditional method (which works fine, as far as I can tell) is with a silicon\wax-based sealer, which you (the homeowner) apply yourself (wipe on, wipe off) every 6-12 months or so. The second option is a (hopefully) more advanced approach that actually bonds a teflon-like substance to the granite, and has the advantage of lasting much longer with little to no maintenance other than normal cleaning. I would not have known about the second option except that it was mentioned by our mirror guy, Jim from TLC Windows. Jim recommended that we pay a little bit extra to have our shower walls treated with Hydroshield, which we did, and he also mentioned a similar product for use on granite countertops.
Later on, I found that Stoneshield was the Pacific Northwest dealer for this product and I decided to contact them. Stoneshield is run by a couple named Jim and Kimberly, and their website says to call them 7 days a week, as late as 9pm. Half-thinking this was a joke, I called them a few days ago at 8:55pm - lo and behold, Kimberly answered and answered all of my questions for at least 15 minutes. Jim from Stoneshield met us at the house on Christmas Eve morning (which we greatly appreciated, being so busy right now). After some discussion, we went ahead and had him seal all of our granite. This method is more expensive than the traditional sealer treatment, but I hope it pays off in the long run.
My initial impression of the results is that the granite is much, much smoother than before (almost slippery). Time will tell as to the other benefits, but since having the treatment done, I have heard other positive feedback on the product (from a friend of a friend who works in the granite business).