My only recommendation is to buy from a place with a liberal return policy.
I got some boots from REI (maybe Asolos?) - my husband LOVED the male version, my SIL loved her boots that were the previous rev of the same style. I got blisters on every single hike for 2 years, thinking "Oh, I just need to break them in a little more. Oh, these socks were weird. Oh, it was just a really long hike." and so on. I returned them, got some different boots (Salomons, I think), and it was like a miracle.
No matter how comfy they are in the store, you can NEVER be sure until you wear them a few times. It totally depends on your feet.