I would like to give customers the option of paying however they can whether that be through a proper gateway (e.g. SagePay) or through something else such as PayPal, Amazon Checkout or Google Checkout.

Personally I have not bought anything through the Amazon Checkout except for on Amazon.co.uk and my PayPal buys have been limited. As for Google Checkout I have no idea what that is or how it works from a consumer perspective.

I understand that people buying from smaller sites are happier to pay by PayPal as they have an account already and trust PayPal.

As for Amazon Payments and Google Checkout, do people actually use them if given the choice? There are a lot of people on Kindles these days, happy to buy stuff via Amazon on their Kindle. Would Amazon Payments make sense to this growing crowd?

With too many payment gateways on offer it might be confusing at the checkout. Does anyone know if this is a problem for genuine customers?

I also have not seen many 'pay by Amazon Payments' icons on websites (you see PayPal all the time). Does advertising the fact that you can pay by Amazon Payments increase sales, e.g. to Kindle owners that have a nebulous book-buying account that 'their other half doesn't know about'?