Was really happy to see this feature added, and has revived my interest in EE again, away from SO.
I have answered 3 question but was unhappy with result. The first was a student wanting their homework done, a job I would normally avoid, but didn't know the type of work until I accepted the offer. They reluctantly bought 15 minutes of work but still wanted more free help beyond this. Second client wasn't able to start a session, even with help desk support. Third client wanted everything done in the 5 minute free period (which he though he might be paying for), but would not clarify his/her question beyond a 2 line description. Then stopped contact and gave me bad feedback.
Perhaps the client instructions need to be made clearer. This service could work so much better if you could encourage more business like clients.