If you want great sound then neither!!!!
The Bose (as with all their stuff) is a box filled with very cheap components, cobbled together with no real thought into tuning the enclosure (hence the big bass, not much detail result).
And the Zeppelin is nothing more than a small amp paired with a pair of MT-1s, that have been laughingingly tuned with twin bass ports to produce some ***** upper bass to accompany the steely tweeters.
Why is it that this stuff gets innovation/sound accolades, when it is nothing more than the typical £200 CD/CASS/RADIO unit you'd have bought back in 1990, but with CD, cassette and radio ripped out and an ipod dock stuck on with a 100 more notes added to the price tag!!!!?
If you want to get the best out of your mordern day walkman (the ipod ain't proper hifi) get a half decent ipod dock (onkyo dsa3x), decent amp (maybe a Rotel RA04), and some proper hifi speakers (like Focal, Rega, etc) - and not the chinese tat mascarading under the original names (Denon, Marantz, Cambridge Audio, Wharfedale, Quad, Mission, Cyrus, ugh the list goes on)
And for god sake rip the CDs using a secure ripping program (EAC, DB Poweramp), into WAV or Apple Lossless, rather than relying on Itunes/media player