I plan to buy a used iPod solely for the purpose of installing Rockbox on it. Is there any reason (other than disk size) to buy a generation 5.5 rather than a generation 5? A 60GB 5th gen costs considerably less than an 80GB 5.5 gen, and the difference in storage space alone is not worth the extra money (at least, not to me). What difference, if any, would there be in either (a) the stability of Rockbox or (b) the performance of the Rockboxed unit? Thanks!