All of the teams who finished in the top 6 aren't doing well at all, Leeds, maybe Saints the exceptions and Wigan are starting to pull it together.
Table last year:

Saints - Haven't played well, scraped a couple of wins and could have lost last night along with the loss to KR
Leeds - Not on fire, but 100%'s all you can ask for
Catalans - Only win against a shocking Warrington
Wigan - Poor start, but good performance yesterday
Bradford - Interuppted start to the season but really do look poor.
Warrington - Woeful... enough said

Hull KR - Good start, seeing their opening fixtures
Wakefield - Same as above, and their fixtures haven't been easy as well
Harlequins - 2 wins out of 3
Hudds - Beaten Catalans and Bradford - two play off teams last year.
Hull - Top of the league
Cas - 3 wins out of 4

Salford - Poor start
Celtic - No points, but they've ran some teams very close.

I was looking at the table like this earlier also.

Only 2 teams from the top-6 last year in it this year.

Very early days yet, though.

Indeed, it's a marathon not a sprint.

Perhaps more shocking is the lack of threads about poor refereeing ruining the start of the season.