Murdock,
So far the only issue I have had are as follows:
1. At times Google can't find the call back API URL
2. The Google Checkout orders are not coming through my admin panel
The good news is that the shipping comes through fine, the taxes come through fine, no problems there. As far as the orders go, Google does send me an email indicating that an order was placed, so all I need to do is go to the Google Checkout page click on my orders, and take them from there.
I sent a support ticket and Chris is working on this. Not sure what the deal is with the call back URL, google says it can't find it, I think it's just timing out. Anyway, these guys and gals at Americommerce are the bomb, I am sure they will have this figured out soon.
The cool thing is that I was able to put the Google Checkout in a custom html snap in on my sites right column, in that column I have a shopping cart that is visible to the customer as they are making their purchases, if they decide to go with google checkout the button is right there and all they have to do is click on it. Here is my URL www.TackleToyStore.com you can see it there. I think it's pretty cool, and it eliminates the need of having to put a merge code on each and every single product that I have!
Best Regards,
Louis
TackleToyStore.com