Through October 15, 2013, British Airways is offering a 25% bonus on the conversion of hotel points to Avios. The partner hotel programs for this promotion include Club Carlson, Hilton HHonors, Hyatt Gold Passport, IHG Rewards, Marriott Rewards, Golden Circle and Starwood Preferred Guest.
British Airways Avios aren’t the most valuable points currency out there, even though they’re incredibly valuable in select markets (like for shorthaul awards, given the distance based award chart).
I think the only partners with which this promotion could make sense would be Starwood and Marriott. With Starwood you get a 5,000 point bonus for every 20,000 points transferred, so factoring in the 25% bonus you’d get a total of 31,250 Avios for every 20,000 Starpoints transferred.
Meanwhile with Marriott, your best bet would be to take advantage of a “flight and hotel package,” whereby you can redeem points for a set number of free nights and miles.
Personally I love British Airways Avios, though I love sourcing them from Membership Rewards points transfers when a 30%+ bonus is being offered, so this isn’t a promotion I’d take advantage of.
(Tip of the hat to Matt)