I recently installed a B17 Narrow, and its still breaking in (so can't give a full review yet), only 100-150 miles on it probably. They take at least a couple hundred to break in, if you have soaked them in something like neatsfoot oil. I've heard its more like 500 miles if you use Proofide.
I've never heard a bad review about a Brooks, for what it's worth.
Sheldon Brown probably has a few things to say on the topic, http://sheldonbrown.com/leather.html
This is definitely a question for the Search function. Meaning, you aren't the first person to ask it. Not by a long shot.