One data point
Here's a real-world example:
I ride a Rotator Tiger
, a classic high-crank, reclined (more than the pics) SWB. My wife rides a RANS Stratus
, a classic LWB. I can climb the nearby 1.5-mile, 9% hill at about the same speed on either bike, even though they are set up quite differently. However, coasting back down that hill is a different story. I have yet to reach the Tigers's max speed - I always end up braking just under 50 mph. On the Stratus, I have to pedal to maintain 35 mph.
While both bikes are quite comfy to me, and I can ride either one at 16-18 mph for miles, a headwind affects the Stratus almost like a DF whereas the Tiger almost ignores headwinds. So for (unfaired) racing, or real-world battling headwinds, the reclined SWB Tiger wins hands-down. For sheer crusing comfort, especially on rough roads, the flexibility in the Stratus' long frame is great.