The most suprise for me there is Chelsea as they didn't look like a team that could be in the top 4 position this season although they shouldn't celebrate yet as they're on th same points with others below them and one game lost alway from falling off the top 10 position as other teams are just one point below while others are two and three. The table position is going to be different after the international break as players will return back having injuries or feeling tired and they can't perform as they use to do. making other teams to have the opportunity to go up the table.
Chelsea have had some bad seasons therefore it is not strange to doubt their ability to be in such as good position now. Enzo Maresca didn't also look like a coach who would clean up the mess other coaches left behind. The new coach has helped many players to improve and the playing style of the club is now commendable. Just as you rightly said, the league is still early to conclude that the Blues will qualify for the Champions League this season.
For Manchester United it is difficult to predict how their season will end especially when Van Nistelrooy will not bee in charge anymore, he has brought about change in the performance of thee team but now that he will not be in charge again no one knows how the performance of this new manager will be but i am certain that they can at least challenge for a spot in European competition next season.
Considering the calibre of coach that is coming in to take over the managerial position of Manchester United, one can assume that they will keep having good results. Ruud van Nistelrooy would have been my choice but it seems the club want a world-class coach.