It's hard to believe that Houston is going to take Clowney. Bill O'Brien is a very no-nonsense type of guy, and I don't think that Clowney would fit in very well. Besides, if I were Houston, and I wanted someone to compliment JJ Watt, I'd get Mack. Mack is a true Clay Matthews-esque player who could come off the edge and do some serious damage, but also drop back into coverage and play great defense there.
I agree that Mack is a good player, but there is NO ONE as physically talented as Clowney this year...and it's not close.