I would caution you from judging all other agents based on your experience with another.
Why do you think the process was so fast and seamless when you dealt directly with the listing agent? Dual agency is a VERY grey area. I have never understood how an agent could actually best represent the interests of dualing parties who have competing and conflicting interests. Curious, isn't it?
Whenever I have sold my own listings, it has been as an acknowledged Seller's agent to all parties.
That being said, if you don't truly care that your best interests are protected, I, too, will throw my hat in the ring by providing you a direclt link to public MLS searching...