It is far from over. The race is just beginning. But performances mean something. And their performances are far better than everything they showed last season or under previous managers. Meanwhile, United are not very convincing in away games. Stoke, Soton and Liverpool were nothing special, even Swansea for 80 min. wasn't particularly good.
And you are quite wrong. If United were playing like City and were getting such results, the forum would absolutely explode. Tell me when was the last time when United dominated in a big game away like City did vs Chelsea? That was great footbal from start to finish.