This is basically the only regular universe X-Men title I read. Minus the Deadly Genesis miniseries, because Brubaker is an awesome writer.
I'm not a Whedon fan, and don't take that the wrong way, I really don't have much of an opinion on him as I didn't watch Buffy or Firefly, etc.
But he knows how to write an X-MEN comic. It seems a lot of writers lost that along the way. I hadn't read an X-Men comic in a little over 10 years before picking up Astonishing once again, thanks to a recommendation from Elijya and others.
But the latest issue, # 15, was definitely picking put pace for this latest arc. And when Wolverine got transformed, holy crap, probably the funniest moment in comics THIS YEAR, by far. I laughed for a good five minutes at that.
But props to Whedon and especially Cassaday...his art is just beyond fantastic at this point. I hope that Marvel has this guy locked down for their sake.