I might be wrong, but I don't think that can work if you want to accept credit cards directly in order to keep customers on your site for the whole checkout process. These type of solution also rarely let you set up recurring payments.
I think most of them have supported recurring payments for some time now, certainly Avangate and FastSpring both do.
One big missing pain: EU VAT taxes. According to the law you're supposed to tax EU customers if your business is in the EU. Obviously the tax is different for each country and changes from year to year: https://en.wikipedia.org/wiki/Tax_rates_of_Europe . Businesses with a VAT ID can be exempted from the tax but only if they provide a valid VAT ID. At the end of the year your business then provides the list of transac…
When you use a full-service e-commerce service that serves as a reseller and is the merchant of record, taxes become their responsibility, not yours. At FastSpring, we handle VAT and have dealt with all the different issues that come with it: real-time VAT ID validation, exemption for B2B customers, being able to display prices using VAT net pricing mode or VAT gross pricing mode, and so on...