I ran across an announcement for Paypal website payments pro. It seems to make adding paypal a resonable option to your site. The changes are that your users can either express checkout through paypal or select "normal" credit card processing. If they select normal credit card, Paypal actually does the clearing in the background. It's transparent to the user.
The fees are low and they do all four major credit cards at the same rate.
Paypal lists shopping carts that will accept this solution, but Miva is missing. I contacted Miva and it appears that they will not be embarcing this.
I like the service I have at Westhost and the bundled package works well for me. Does anyone know more about Paypals Website Payments Pro and what might be happening with Miva?