I have had some success in crossing-over their cards, too. However, my success is primarily focused on more modern cards. I have heard anecdotes from some vintage afficianados that CTA is not always efficient at catching trimmed examples -- but I do not have any knowledge that will either confirm or deny this.
As their business model focuses more on the computerized element than the human element, I think that there will continue to be a risk associated with their services -- a risk that is perhaps enhanced when you are dealing over the Internet than at a live show.
"It is not the critic who counts..."