I like my B17. At first, it was very slippery and rock hard, but the slipperiness soon wore away and eventually the leather softened. Now it's my most comfortable saddle.
I can't imagine what it would take to wear the Brooks in and why would I want to put up with it.
In my case, it took about 100 miles for the slipperiness to wear off, and about 1000 miles to break in the leather. In terms of time, that translates into about 2 days for the slipperiness and a month for the break-in.