I set up a client on Google Check Out and it went very well. Simple. There were things that I thought were better than PayPal but can't remember exactly what they were.

I think you will see a similar result as PayPal. The more options you give the better off you are.

advantages of Google checkout:
-bolded adwords listings with the cart icon displayed
-easy to tie it in with google analytics and adwords for tighter ppc reporting
-google handles the card processing fees
-much like paypal and 'bill me later', providing another strong 'brand' payment option
-some kind of premium visibility will most likely happen down the road...something to do with google shopping/'base' aka froogle.

disadvantages:
-providing google with inside info on conversion data..gives them more info as to the $ value of certain phrases...may impact cost per click in the future
-integration. I know for us it was not possible to use goog checkout due to database issues.
-can your existing metrics package track it as well?
-not necessarily proven to improve site conversion rate, particularly for trusted/credible brands.

I'd do 'bill me later' if you haven't already...just my .02

I use Google Checkout on my site and try to use it on eBay sales too, though eBay have banned it as a payment method as it was free for sellers last six months. It's brilliant. Never one problem and all fee-free up to this point.

Probably more to do with the fact that eBay owns PayPal.

Yes, was doing some work with eBay when they bought Paypal.

Have used it several times and worked great. Anything to not support Pay Pal is good.

I like Gcheckout.

I hate PayPal - you can read their rap sheet (list of court cases brought against them by the Attorneys General of various states + many screwed over individuals) to find out why...