I recently had a Modigliani painting appraised by an agent at WhatsItWorthToYou.com. I’m very happy with how well the item was appraised. It was a very knowledgeable response and on the parts that the appraiser wasn’t (and couldn’t) be sure about, she referred me to other excellent sources.
$20 didn’t get me a perfect appraisal but it got me a LONG way along the road. Sotheby’s and Christy’s wouldn’t discuss it for less than 4 figures.