VS is Vibrating Shuttle - it has a long shuttle/hook that moves back and forth instead of a round shuttle/hook that moves in circles (either all the way around (full rotary) or back and forth (oscillating, like a Singer 15).
VS machines come in two basic types - those that go back and forth, and those that go side to side. Typically the side to side are older machines, often with "boat" shuttles instead "bullet" shuttles.
As to Feet - often the feet between a Mfg VS and Rotary machines are interchangeable, but not always. However bed mount items (like the shirr plate and underbraider) are often unique as most of those for the VS machines are hooked to a plate that slides in place of the front throat plate.
Last edited by Macybaby; 11-19-2014 at 10:18 AM.