Auction Checkout sounds great--except for those monthly fees. Having to pay up to $40 a month for the privilege of using the service, plus per sale fees, I just don't see a savings there. Of course, I'm not a PowerSeller yet, just a little person in the pot. For people making megabucks on their auctions, this could be a good thing. For us little fish, not so much.
PayPal is free to set up and there's no monthly fee. That's why I settled on them in the beginning. I've been using them for about three years or so, and only this past summer had any trouble. Nothing horrible, and it was taken care of.
I've bookmarked Auction Checkout anyway just to keep it handy for down the road a piece.
Anita