DDC may be slightly faster (UMN is averaging about 2 weeks), but please note: You cannot submit test results to the OFA database - it says right on the DDC web site that OFA will not recognize results of this test.
Furthermore, please keep in mind that the folks at UMN put so much time and energy into the research. Their test is reasonably priced. What incentive is there for Researchers to put their energy into genetic research for our Labradors if we thumb our nose at them by going to labs like the DDC.