The Virtuemart RSS Feed, has 2 versions at present. Below you can see the differences between the 2.

Both Versions have these attributes 

• Product Title
• Product URL Link
• Product Description

But these are only on the Froogle version.

• Product Condition (New or Used)
  
• Product Expiry Date (Data information expiry, not perishable goods expiry date)
  
• Product Brand (Taken from manufacturer in your system)
  
• Product Image Link
• Currency (GBP or USD for example)
  
• Product Price
• Product Type (taken from the category it is in, within your system