I did some bechmarks of three different SDHC Cards in an USB-Reader.
In this case the 4 Gig card performs bad at short read/write cycles. If you're lucky a class 2 card performs like class 10 at big files (saw that in benchmarks) or as bad as this one.
My personal usage of the SDcard is only for Backups, Images, Music, and Films/Video, so my next one will be a 32 GB Samsung Class 10 which reaches up to 20 MB/s.

Post your benchmarks.


4Gb class 4
--------------------------------------------------------------------------------






8 Gb class 2
--------------------------------------------------------------------------------






16Gb class 10
--------------------------------------------------------------------------------





--------------------------------------------------------------------------------


16 GB Samsung class 10 benchmark from another forum:
amazon