Austen was able to get some good character notes, but the ideas he used them with read like they came out of a drug induced stupor. Specifically, the drug induced stupor of someone who has less creativity than 90% of the people posting on these boards.
Nightcrawler, Son of Satan...er..Azazel, Warren basically being an actual angel, Nurse Annie's romance with Alex while he was in a coma (still better characterization for Alex than Remender though), several other things that take the route that would be most obvious to someone who has never picked up a comic book, much less an X-book, and the high point of his run, Sammy (fish-boy).
Bendis's problems are 'Bendis-speak', where everyone talks in the same voice (even if the personalities are obviously different even under Bendis), and a complete inability to do a decent follow through, instead relying on meandering, meaningless filler. Guy managed to take what should have been a two to three issue arc and go for 9 or 10 issues - it was an event tie-in that wasn't finished until the event after was complete. I still say very few people can set up a hook like Bendis, but I think I'd trust any of them to finish after the first issue to two over BMB any day.