I like both of them for very different reasons.
I like the Elegant Beauty Sierra because IMHO, the platings (espically the Ti Gold) looks much better AND because my male customers seem to perfer the larger diameter and the slightly longer pen.
I like the Dayacom Elegant Beauty (Aero) because the top twist works very nicely and eliminates the customer "unscrewing the body, before pulling the pen apart issue" that will eventually cause the customer a problemwith Sierras. My female customers like these better than the Berea because they are fitted and balanced for a smaller hand.
Depending on where you buy these sets, the price is very close on both sets, so I make and sell both.
FWIW, a Private Reserve EZ Flo 9000 makes both of these pens outperform the $400 Mont Blanc Miesterstuck!