I saw his last game and he certainly wasn't crap. I remember one amazing run where he almost ended up smashing it in the right corner, but it hit the net on the outside after passing 3-4 players. That run alone shows his qualities and undisputed, ridiculous talent. All players have "bad" runs, attempting to play him down is just utterly futile. Being so young certainly dictates that he will struggle with consistency, but over the next 2-3 years he will only develop and pick his battles carefully. Comparing him with Rashford is also a bit lame, as Mbappe does things Rashford would not be able to. That's not saying Rashford isn't a hell of an exiting player too!
You often see the greatest players having their own, unique ways of doing stuff - often things that haven't been seen before. Messi's touch and way of running past multiple players before passing/shooting into the corner (hard to describe, I guess you know what I'm trying to say), Ronaldo's stepovers and inside click-passes that he made his own, Zidane's turns and Ronaldinho's everything. Mbappe has that too, in the way he dribbles and leaps past players with extreme pace, his shift of tempo before leaving players behind him. A bit like Pogba actually.
I am not getting into this contest about Mbappe and Rashford, I just hope both of them stay fit for 15 years, because Messi and Ronaldo are leaving behind huge shoes to be filled.