Thank God for this thread. I am using my E280R as a backup player for my Sansa Fuze and the cut and paste feature saved my butt.
My 8 Gig SDHC card is not recognized in my E280R under original firmware, but of course is recognized under rockbox.
I found this a neat "disaster recovery" feature in case my SD card ever gets wiped.
I erase the content on my main memory. Copy my "SD Card" content from the computer to the main memory, then use cut and paste to move it out of main memory into the card. Then I reload the main memory.
It is not a "fast" process by any means, but It's nice to know that it works (I've tested it), so if I am without access to a reader, I can still get content to the SD card via the Sansa E280R, even though it might be a two step process.
Another great feature of Rockbox.