Accepting on-site payments on your own site comes with a lot of liabilities and administrative and technical hassles:
Your hoster, server and site must comply with PCI-DSS requirements, you must do quarterly PCI-DSS security-scans of your site and server, and pass a yearly audit of your company and site that you have to show to your acquirer for compliance. Additionally, despite those stringent (and evolving) requirements, you stay liable for card-numbers thefts or hacks from your site, even if they are not your fault (e.g. hoster has bad security).
Are you sure that you want to collect sensitive financial information on your own site ?
I didn't know that and I don't think my US partner did either...
I was always in favour of the simpler PayPal standard solution but he insisted on taking credit cards without leaving the website. He may think about it twice now with this new info...