I have the same foot "specs" as you, (aka size 11 and narrow.) I have a pair of Lowa's that are just awesome for my feet. After 7 seasons they're showing their age and mileage so like you, I'm starting to look at replacements.
When I first tried these on in the store they fit like a glove. Instantly comfortable, with really good heel retention. They've been great ever since.
My replacement pair might also be Lowas but I'm also eyeing lighter synthetic boots purely for weight savings. The other day I tried on a pair of synthetic Scarpas that fit like a glove. They were awesome, but not high enough. Next boot I try on will be a high-top Scarpa.
Couple things I do when trying out boots:
- I bring my orthotics with me. I pronate a lot and so the corrective footbeds make a big difference in any boot. If you have a specific insole you'll be hiking with, it only makes sense to try out boots in the store with your specific insoles.
- Lace up, walk around, and check for any heel lift. I've found if a boot is not giving you really good heel retention, the likelihood for blisters on the back of your heel is very high.
- A good boot should feel comfortable right away in the store. No obvious pressure points, heel lift, "slop" from being too wide, etc.
Just my two cents.
Good luck boot hunting!