I've found lightweight flannels to lose their shape over the course of a workday, and pill quite easily. They often need to be re-pressed after every 5-6 wears (even though I never wear them on consecutive days, or more than 2x a week). As I mentioned, the three that I own are from Fox and Drapers, so the merchants / mills in question are top-notch.
My 15oz. Minnis, in contrast, performs admirably.