The positive first: the card works in Pi B +, have the newly installed.
Unfortunately, the transfer rate falls to me worse than in other recessions.
Both the Pi (ext4) as well as on the notebook (FAT32, MacBook Air anno 2011 Windows8) I come to 18-20MB reading and writing about 14MB (sequentially).
Is naturally from within the specs, but far from the hoped and advertised rate.