Thanks guys, its always puzzled me, though I sort of guessed at the Aero benefit
Ah, the slippery slope. Next you'll want to try one, just to see. Then, we have you....
Although I'm not a total 'bentist, I have uprights for day to day use and convenience. But if I had a garage at the flat, and a Brompton for train travel, I'd use my trike much more and maybe ditch the 'normal' uprights - currently it does leisure rides of any distance, because of the comfort aspect.
(Seriously, if you get a chance to try one, bike or trike, then do. If you're ever likely to be over East Anglia way, Kevin at Dtek does 'experience' sessions where you pay a small fee and get to try all sorts. Don't be put off if a two wheeler feels wobbly at first, it's just a case of re-jigging your balance a bit. A trike will just be easy.)