What I meant with Masterpiece is that it actually integrates with such systems. I don't know if the others do or not. For example, your PC (that you already have) with Masterpiece on it turns into your POS system as well as your inventory management, web management, and invoicing systems. You can attach a bar code scanner, a credit card reader, cash drawer, etc without needing to pay the overload of money for the full POS system that would be redundant.

Personally, I think that you'd not need everything that a POS has. A bar coder scanner would be redundant if everything's unique and easily tagged -- might as well punch it in. A pole display and a credit card reader are both very useful, though.