hi kms108, I see you own an Xperia Ray. Did you try the 64gb sd in the Ray? Can you share with us if it works or not? While Googling I only find people speculating that since it works on the Play, it should work on the Ray too, but I hope you can confirm this for real..
will try the card at the end of the month, the 64GB card recenly had a bid drop in price in hong kong from HKD 1000 to hkd 540 (USD 129 to USD 69.50) will get another soon.