I'm a relatively high-volume Google Checkout user, and you can see during these time periods that orders just completely stop coming in. Users attempting to purchase and sometimes even sellers attempting to access their account get redirected to this error page. Like many sellers, this has cost me substantial amounts of money this week, and on top of it all, most of us are paying for Adwords at the same time Google Checkout is down, so not only are we losing revenue, we're actually paying Google to send us customers who can't make purchases because their system is down.
On top of all of this, Google Checkout offers no phone support, and it takes the better part of a day for their email support to get back to you. They do acknowledge that the system is having difficulties and say that their engineers are working on the issue. Well, that was Monday. It's Friday and not only was the service offline today, but many sellers (such as myself) have orders backed up in the system for hours, and in some cases for over 48 hours. This means that in some situations, orders placed 2 days ago have not yet been processed by Google, and remain in one of several pre-charged states of "Reviewing", "Chargable" or "Charging".
It never even occured to me when switching from Paypal to Google Checkout that the service could be this broken. Google does everything so well, so one must ask himself, how does a company like Google screw up something like this so badly?"