Not sure about sponsors but I have been using the twin walled Biocups from BioPak. While they are Sydney based they have a Melbourne warehouse so quick delivery is easy.
Heat retention is excellent and taste or lack of it is good too compared to others. They also do PLA (corn starch) lids for a few cents more than conventional plastic. Also they have PLA cutlery as well.
As to value no they are not the cheapest but they look good and I regard them as a selling feature over others locally.