Google Checkout and PayPal are really two different programs. They do both have their disadvantages and their advantages in using either of the programs. In all the programs, they have some type of invoice system that is already set up. So, lets look at it in 4 sections.

PayPal's advantages: The biggest advantage that PayPal runs, is it is international and can be used worldwide. PayPal also offers a credit card in conjunction with their services. And, on top of it all, you can store money in your account with PayPal. Also, it runs well with EBAY.

PayPal's Disadvantages: You are charged for every transaction that you run into PayPal. I had a customer send me $250 and I end with $247 and some odd change. Losing money during transactions is not something that I am keen on. Also, another issue with PayPal is they are always a target for hackers and phishing schemes. I can not even begin to tell you how many times that I have received phony emails. The last that I will expose is the fact that PayPal will only allow for one PayPal account per Checking or Savings account. So, if you have a joint account, only one can use PayPal.

Google Checkout Advantages: If you have a Google account and use AdSense and AdWords, must fees through CheckOut is either refunded or waived. Since this is all through Google, they believe in sharing in the wealth. Google Checkout is easy to integrate into your website and can easily be used to add a buy it now button in your website that will take you to Google Checkout to process your order.

Google Checkout Disadvantages: I have to say that the only disadvantage that I have encountered with Google Checkout is that they do not allow for storage of funds. This slows the process a little when purchasing through a bank account.

Now, with all this said, I think that the best system around in the US at this time is Revolution MoneyExchange. There is no fees at this time to send or receive money and can be integrated to your website to allow your customers easy purchasing. It is quiet frankly the easiest system to use and one can sign up for an account and be on line running in no time. I have found no flaws with this system yet except that they are only in the United States.