[RoyBoy]

I have had both. For building electric guitar bodies, the oscillating spindle sander is terrific for truing inside curves on the waist. The advantage of the disc sander is you can produce perfect flat, 90º angle surfaces- like the bottom of a nut or saddle- or an angle you want without having to depend on the steadiness of your hand.

Whichever you get, get a range of belts from grits 80-220. The tool will remove material fast. A finer grit gives you more control- I'm surprised how often I ended up with the 220 belt.