None of them look substantially different. I'd also consider Shimano brakes a plus also. Also, it's worth checking in whether the rims (and to a lesser extent the tires) are designed to be run tubeless, as that can make a big difference in performance. As far as I know, the Specialized has tubeless ready rims, and the Trek has tubeless ready rims and tires (probably just needs a valve stem and some sealant and good to go). The other two seem like they don't have tubeless ready rims--you can probably convert them, but it's more hassle and may not work as well. Also, for what it's worth, the Devinci is the only with a triple, though it's your call if that's a plus or minus. The bikes you're looking at should all be lots of fun.

Also, it's genuinely important (particularly if you're new to the sport) to pick the shop that will best help you. Factor in any services or discounts they may provide with sale when comparing shops. Some help dialing in the fit and the suspension could go a long way to getting you ripping harder sooner.

For what it's worth I ride a '13 Carve Expert and like it pretty well.