I'm not prepared to wear the enormous devaluation this causes. Marriott do it stupidly, so that you can lose a lot in the conversion. For example, if I'd put my last Marriott stay into Marriott Rewards and had that convert to Qantas, I'd have received 675 QF points. By putting it directly into QF, I received 1000.

(To make matters worse, since Marriott failed to credit it initially, I contacted them and, instead of crediting my QF account properly, they found my unused Marriott Rewards account, and put the points in there anyhow! It took months for me to get them to reverse this so that Qantas could make the correct credit to my account.)

Starwood do it properly, crediting the same min points to your airline account whether you put it through SPG or not. (And that means you get the stay credits too as well as the min. mileage.)