Just my opinion, and I haven't ridden either, but for longer distances I would usually opt for the most comfortable geometries. Now, that's not saying what is comfortable for me is comfortable for you. In general, a more relaxed geo is more comfortable for longer hauls. Looking at the two frames in topic, and at 58-ish sizes, the seat tube angles are similar and not too steep at 73.5 (BN)/73 (SR) degrees. The head tube angles are a degree different at 75 degree for the BN and 74 degree for the SR. (Of course wheelbase length has a factor in ride quality too but I don't know the length for the BN - the SR is )

Having said that, I also want to add that when I was shopping for my first dedicated single speed, I was concerned about more agressive frame geos. My only intent was to ride on the road for 1 to 2 hour rides. Because of this I wanted a more relaxed frame. My single speed conversion road bike has a 73 degree seat tube and a 73.5 degree head tube, which I wanted to try to stay close to when finding the dedicated single speed. The bike I ended up getting was a Madison due to the sale they had on them, and among other reasons. This bike has a 74.5/74 head/seat tube angles which concerned me about longer rides. I figured if it wasn't comfortable, it would just be a short distance/errand bike. Turns out that I have been on this bike for 2 hour rides with no complaints whatsover.

I think in the case of the one degree differences between the BN and SR may not concern you in the ride distances of them. You can always make up the degree or so in component fit setup, i.e. bar stem height/reach and saddle fore/aft.