As was mentioned, aerodynamics are vastly improved on a recumbent, even just a high racer. Comfort is huge, and if that were the only gain that'd be worth it to me.

To illustrate this in a more tangible way, I have compared electric bicycles using a vision R54 and an upright. With an average speed of 20mph for both bikes I'd have a watt hour per mile of around 13 on recumbent and 26 on an upright.

This different in aerodynamics, of course, matters more and more at faster speeds, OR, with greater headwinds. Whats that I say? Yes, on a windy days it's way way better to be on a recumbent no matter your average speed.