Wirelessly posted (BlackBerry8530/5.0.0.601 Profile/MIDP-2.1 Configuration/CLDC-1.1 VendorID/417)

I think a lot depends on your intended use of the miles you accumulate. Where do you want to go with them, from where, and in what class of service?

Even if you expect to primarily fly BA on your paid travel, you might be better off crediting the miles you earn on those flights to a BA partner carrier, like AA.