Ask HN: Good outsourced XHTML/CSS development companies?

Does anyone have any experience with outsourced XHTML/CSS developers? People like http://www.psd2html.com/ or http://www.psd2htmlninjas.com/ ? I'm trying to find a high quality supplier but haven't got any first or second hand experience with these sorts of companies.

Quality of work and turnaround time are the most important factors for us, as I would expect it is for most people.