Tcook52 is correct in pointing out the bonus miles for BA transfer is only 50%.
It also depends on what you need for awards. BA charges high amounts for J and F awards but it does have MFU (upgrade awards) for 25k per RT Canada to UK but some Y award are lower in miles than AC.
I also like MBNA SPG card since I can also redeem it for hotels nights or flight and miles. But only good till 30K spending.