PE 700 II memory card only and no disney designs
PE 770 both memory card, and usb card and no disney designs
PE 770 FS (which I believe should be DS) will be memory card, usb card and disney designs. If you plan on doing any disney designs at all or think you might always go with the DS at the end of the model number. I hope this clears this up for you.
So better of the 3 PE770 DS