Hey, John. Welcome.
Some good advice so far. I tend to agree that the bike shop is the thing to look for. As Bill pointed out all of the models you're looking at are pretty solid. I will say, the disc brakes are much more powerful under a variety of conditions than most other brakes. You may not ever need that additional stopping power. Keep in mind that many who work in bike shops ride and ride hard. Their sense of what is needed may not be based on your actual needs. With that said, having disc brakes can't hurt. Oh, one other thing. A deal is not a deal if the bike doesn't fit you properly, is a mismatch for your needs, or isn't supported by the shop from which you purchased it. There are many threads on Bike Forums where folks regret going for price over other considerations. Good luck with you choice.