USB adapters for RS-MMC?
 

I am deciding whether to spring for a USB 4GB flashdrive or whether to get a USB adapter for my MMC and SD cards. The obvious advantage of the latter is that I can easily iinput my data into handhelds or a PC. But are there any performance disadvantages to the USB adapters? I'm mostly speculating that the adapters might cause a decrease in transfer speed for large files?

You cannot use the 770 in USB host mode without tweaks to the OS and a voltage injector to power the device. Check out the wiki for more deets.