There is a lot of information about storage devices on the Squeezebox forums, so I would recommend you take a look there.
One of the major differences is that a NAS device has a small processor and operating system. Many come preloaded with the Squeezebox server software, so the NAS can serve all your music files without the PC (or Mac) running. They can also come with multiple drives that can me set up in a RAID configuration. Overall, more powerful, but also more complex.
One of the major differences is that a NAS device has a small processor and operating system. Many come preloaded with the Squeezebox server software, so the NAS can serve all your music files without the PC (or Mac) running. They can also come with multiple drives that can me set up in a RAID configuration. Overall, more powerful, but also more complex.