What I know about Bill Kollar is this: he's one of the most well-respected defensive line coaches in all of football. He's an intelligent, passionate, forceful coach that values character and consistently hard work. He gets the most out of his players. He's as good a position coach as you can find in today's NFL.
I'm pretty ambivalent about the vast majority of Buffalo's coaching staff, but Kollar is one guy I had no qualms about. His lines produced everywhere he went before he came to Buffalo; don't let the fact that Buffalo's defensive line has sucked for the past couple of seasons allow anything positive you've heard about Kollar to be tarnished. The Bills simply don't have enough talent along the line; there's only so much turd-polishing that one man can take. I'm certain that the opportunity to coach the likes of Mario Williams, Travis Johnson and Amobi Okoye was a tremendous pull for Kollar. With talent to work with in Houston, I suspect he'll have his line returning to its productive ways in no time.
Makes you feel even better about the hire, doesn't it? My only concern about the analysis is that word of Travis Johnson's awfulness apparently hasn't crossed the New York state line yet.