Just to pick up the memory card thing:
Read and write speeds of the memory cards make a difference, allthough not too much.
There's a huge difference between memory card and internal reader memory.
I tried this once with a pdf and page load times were reduced by 50%. Initially, with the file on the card, a page turn was about 7 secs. On internal memory it was down to 3.5 secs.
As long as my files fit on the readers memory, I go with that.
