owners of an Archos 500 or later series: improvements?

Hi, if you own one, have you tried upgrading the hard drive? Am thinking of doing that now but would like to know if you encountered any issues, problems of any kind. What happens when you first boot your archos after you changed to a new/different drive? Any re-configurations necessary? Something as basic as did you notice any problems with the original interface, did original menu(main and system) display and accessible correctly? Any input from you will be welcome! Thanks.