FWISmoker,
I agree that a good sear can be had on a UDS with a sufficiently low searing grate. But good burgers and steaks also gain improvement by keeping a moist cooking environment. A ceramic requires a smaller fire to achieve any temperature due to the greater insulation a ceramic has. A smaller fire means less air-flow, and less drying out of the meat. This is part of the reason why Kamados tend to do steaks and burgers so well. Additionally reflected heat from the dome tends to help cook from all sides at once, which helps with the consistency of the cook. I absolutely believe great burgers can be made on a UDS, they are just a bit easier to make to the same quality on a Kamado for the reasons stated above. Or to be more specific, less skill is required on a Kamado than a UDS to get the same results. The OP stated he was accustomed to burgers made on a Big Green Egg (BGE), as such his methods of cooking most likely expect to leverage the strengths of the Kamado cooker. He may have to play with the UDS a bit to learn the differences in cook method required to get similar results from his new UDS.