I picked up a bunch of RO lump last year when it was on sale at Home Depot. I really like it-- probably a tie between that and Frontier as my favorite lump. Though I do find some rocks in the RO lump, which is really aggravating. The Frontier is generally free of debris, though I do tend to buy bags from the US rather than Mexico (I buy the 32 lb bags at BJs, where they tend to stock both versions).
For briquettes, I like Stubb's the best. But that might be because I rant out of Coshell.
I've had really bad experience with Trader Joe's briquettes, and in my experience the RO briquettes are about the same (smudgy smoke, and they crumble to dust before one cook is even complete).
I might try some Cowboy briquettes, but I can currently afford to wait for a sale (aka, I over stocked last summer ;-)