No, the Tyros will not recognize a USB drive. It will however, take almost any laptop-size hard drive.
You will gain a better, color display, lighted buttons, 3 voices on right hand, aftertouch, better keys, more dedicated buttons, more patching capability, better sound (I know there will be arguments but I can tell the difference), a mic input control where you can reach it, more factory styles and sounds. I know there is a lot more.
You will lose onboard speakers.
DonM