The only solutions I know that I can compare at the moment are Paypal, Pin.net.au and direct bank API's.
Paypal is the obvious one of course, but I am not a huge fan, hate their API and don't trust one day the account will be frozen for 6 months from an income spike.
Pin is coming along but is still in beta so we were not prepared to risk it just yet, and forget the banking API's, the costs and hoop jumping is a little silly.
Our solution in the end was Braintree (https://www.braintreepayments.com/) who's API is infinitely easier than Paypals and handles most of the tricky stuff you might need to throw at it being a SaaS company.
Best of luck, hope it helps.