Personally, we use Secpay (secpay.com) and have had a very satisfactory service for 4 years. Of course, you have to be a 'real' company with a company bank account authorised to process credit cards. That is more diffficult to set up than many people think which is why services like PayPal can exist. Charges vary and you will need to work out the most economic according to the volume and value you expect; we are down to £0.10 per transaction + bank charges, but then we do £75K - £100K per month. Easy to set up, easy to brand, and all the technical support you will ever need. Highly recomend it.
PS I can implement the payment form for you in about 1 hour if you do sign up with them.