I haven't heard of anyone necessarily HATING it. I think it is great. The first arc was a little too short and a little unsatisfying, but if Hickaman's writing isn't enough, then Opena's art will at least do the trick for me.
I think it was great too, a perfect jumping point for people who have never heard of the Avengers, except of the movie. And it was pretty much an epic of an pretty much apocalyptic level threat, without it crossing over other titles, definitely better than the New 52 Justice league starting story arc. Yeah Opena's art is awesome, I hope he get to the next story arc ^^.
Fantastic Four and FF are the only Marvel NOW titles I am reading. Outside of that, Captain Marvel, though I may be done with that come issue 10 if they keep issue 9's artist. But mostly, when it comes to Marvel for me lately, I am enjoying the older run from the Sixties a lot more than the modern stuff, hehe.