I've been using Frontier too, and really enjoying it. The pieces are a pretty consistent size-- no real huge chunks. And not too many tiny pieces, either, but a big load of charcoal dust at the bottoms of the bags. I'm guessing that is pretty common with lump.
I sprang for a bag of Wicked Good, and was not impressed-- huge pieces mixed in, and it tastes really smoky to me. If I'm looking for smoke flavor, I'd prefer to add some chunks of alder, apple, cheery, oak, hickory, etc. according to my taste than some generic smoke flavor. The Frontier is nice and neutral.
I've also tried the Trader Joe's (generic) brand, but not enough to have an educated opinion. It's natural lump, but pressed into briquettes with a cornstarch binder, so will not give you the tiny pieces to fall through your grates.