Try them both on in a good outfitter shop. Walk around the store with your backpack (fully loaded) for a while with each boot. If you find a toe rubbing or any sort of discomfort, eliminate that boot as a possibility.

I was told that fit / comfort is paramount in not getting blisters. Second is keeping your feet dry. It doesn't matter how many people swear by this boot brand or that boot brand.

Buy what fits YOUR feet.

For my feet, the Keen Targhee 2 mid fit the best. 500 miles on them before the first blister - and it was from my feet being wet and the seam of my sock twisted around the side of my big toe.
Delamination is an issue with Keens, so either replace them when they start to come apart or keep a tube of shoo goo around to glue them back together.
I have been impressed with their grip on everything but ice.