You can easily seal at home, and you can check when your granite needs to be sealed easily (use the search feature here for tips). We got a 10 or 20 yr sealant and was told I would never have to seal (I didn't know this before hand and assumed I would be sealing it yearly or so). The fabricator told me he will give me sealant whenever I want it, free of charge, I just need to stop by with a jug.

What did granite guy #2 say about *not* sealing?
Is it for the same slab of granite from a yard that you've picked out or different slabs? If so, what did the yard say about sealing that type of granite?
Was guy #2 just the salesman or the actual fabricator?
How much experience did both guys/places have?

I can't speak to the type of granite you have, but hopefully someone else more knowledgable will come in. I'm usually one to go on gut instinct when hiring people...(in addition to other factors)

Some of those supposed "10-year" sealants I have seen seem to add a layer of a plastic finish on the granite.

But even more important, is that sealing granite yourself takes just a couple of minutes. And, depending on how porous your granite is, will be done once a year or a few times a year. The smallest size container of sealant you can buy at Home Depot will probably outlive you at this home (even if it is your forever home!), and doesn't cost much. I don't see the purpose of spending $200, especially if it undermines the appearance of the counter.

But most importantly, I believe Steel Gray granite is one of the bullet-proof granites that do not need any sealing at all. Please see the thread I've linked with people attesting to how tough their Steel Gray granite is. If you are worried, seal it with the inexpensive sealant from Home Depot, and live with it for a while.

It sounds to me like the second guy is looking to upsell you without caring whether you need it. I don't know why you said it seems like a "no-brainer" to use him. To me, it seems like a "no-brainer" NOT to use him. I would never hire a company who did that.

Here is a link that might be useful: Thread about Steel Gray Granite

First guy is the pick of the litter. Dark granites are generally too non-porous to be able to absorb sealer. Applying it anyway leads to a smeary messy problem.

My Steel Gray has never been sealed. You can see mine in the link posted above. Still love it.

I would not put any sealer on it unless you live with it first. As I mentioned in the link above, Steel Gray seems to come in different color patterns. What does the one you are considering look like? Do you have a sample? You should.