title: Amazon FPS vs PayPal vs Google Checkout
body: <p>I'm in the very early stages of planning a new website.  I would like to offer payment processing for two distinct use cases:</p>
  
  <ol>
  <li>Accepting payments from users to me for SaaS functionality on a recurring basis.</li>
  <li>Facilitating payments between users of the website.</li>
  </ol>
  
  <p>The ratio of users making payments to users receiving payments will be approximately 100:1.  I mention this because I want to make sure it is very easy for users to make payments, but can live with some additional hassles for users who want to receive payments.</p>
  
  <p>I have not settled on a business model, but I am considering charging a small middle-man fee in use case 2 above.  I plan on using a python framework to implement the website (leaning towards django or web2py), so existing python module support would be a plus.</p>
  
  <p>My question is this:  should I use a particular payment gateway (and if so, which one) or should I provide support for multiple payment gateways (and which ones)?</p>
  
  <p><strong>EDIT</strong>: How much of a nightmare is it  to roll your own payment gateway? In other words, would it be worth the trouble to accept and process Visa, MasterCard, Discover, etc directly?  Anybody have any experience doing that?  Liability/security concerns more hassle than they're worth?</p>