I definitely recommend aligning your SD card partition's geometry and filesystem(s).
On my 16G, class 6, card, using 128k erase block the write speed has been doubled (from 3MB/s to 6MB/s).
After aligning, it seems that is no difference between bfq, vr or sio i/o sched. I got the same speed with all of them.
Here are the guides:
Speed test apk can be found here: http://android.modaco.com/content/t-mobile...d-speed-tester/