I have love/hate with the B17 on my fixed gear.
One thing I like about is when climbing I can use the back metal support to push my upper thighs/lower butt into for extra leverage. Other 'racing' style saddles I've tried, ones ass pushes over the back of the saddle in similar situation.
I don't like how the B17 sits too far forward, how it sags in the middle as it wears.
I tried a Fizik Alliante to replace my overworn B17, but it just doesn't have that ass bar to push against when climbing seated. Anyone else find this an advantage of the B17?