Yes, CTR does go up with the Google Checkout logo on Adwords.
But, unless you have really happy customers all the time, you will hate their customer feedback portion of it. As usual, it's hard to get happy customers to give feedback but the unhappy ones will always use it to vent.
Then your rating will appear next to your Google Checkout logo in Adwords and you will want to stop using them. At least that's my experience.
As usual, it's hard to get happy customers to give feedback but the unhappy ones will always use it to vent.
But you could deflect that by posting your total Google Checkout #s vs bad results and spin it the other way like "19K sold, 10 unhappy, we strive harder!"
Besides, embrace the bad reviews, fix the complaints, blog about it, show people you really care, you can turn the bad into good if you try, people will be impressed. In reality you want to bring the discussion back to your site and own it, not let Google or a 3rd party own it, that's the way to keep it under control as well.