There are two problems. First the works at the King's Building junction are unfinished. Then a pristine, smooth, recently resurfaced section in Teviot Place has been comprehensively dug up by Scottish Gas.
The opening was due this Friday morning. An early completion of the works at the King's Buildings or Teviot Place looks unlikely.
There are plenty of comments online at various sites about the development of the QBC such as this one - which also provides a map.