the CR-5300 only takes one microsd card and it has a limit on it of 8gb, so it would be better to get the transend adaptor which (as far as I know) does not have a limit.
I'm waiting for either the CR-5400 (the one that takes two microsd cards), or the CR-3100 (the one that takes four sdhc cards) to come out.
If you find where to get either one of those tell me so I can buy it.