So it seems that it is quite good basing on the above answers, and there is an hope for the issue to be solved by BMW. Yesterday I met two M6 owners, and both were complaining about the oil consumption. First one from 13' M6 said that it consumes 1 liter per 1000 kilometers
Second one have bought the 16' car with 14 000 kilometers on it, and said that previous owner already had to add some oil to it between oil changes. Hope that my M5 Competition will be healthy
Looking forward for other people sharing their experience with new M5 Engine in this thread.