I’ve always regarded Starpoints as one of the most valuable currencies. One of the main reasons they’re so valuable is the generous transfer bonuses to many airlines.
Normally, a transfer of 20,000 Starpoints would earn you a 5,000 mile bonus, yielding 25,000 AAdvantage miles. For the month of July, that 20,000 Starpoint transfer turns into 30,000 AAdvantage miles.
The maximum you can transfer in any given day is 99,999 miles, including any bonus. In order to not lose any miles via this bonus, only transfer a maximum of 60,000 miles in any given day, or 90,000 AAdvantage miles.
Starpoints are relatively difficult to amass in large quantities, which is probably the only reason I won’t take advantage of this promotion (no pun intended). The Starwood Preferred Guest American Express card doesn’t have any bonus categories. You can earn some points through referrals of others to the card, but that’s the only other method short of staying in hotels.
Starwood has some truly great properties, and I’ve booked a bunch of trips recently that have dwindled my supply somewhat. If not for that, this is a really good bonus opportunity that I would be taking advantage of.
ETA: As I was completing this post, I saw that View From The Wing was reporting the same bonus is available for transfers to US Airways as well.