I have both styles, and prefer the "regular MTB shoe"
They are actually more comfortable because they keep my feet cooler. They also weigh a lot less, and your feet are an area where less weight is a good thing...even if you're not a cat 1 racer.
As far as climbing hills, MTB shoes will be fine. Maybe better than the traditional hike/bike, because they have much larger treads up front to dig into the ground. They aren't a problem until you have to walk a long distance with your heel much lower than your toes.
Oh yeah...good choice on the Stumpjumper