I started with a stumps gf223 several years ago which is basically his Classic model today. In 2008, I moved up to a Stumps Platinum 6. I have been very happy with his cookers. I don't know what the price of some of the other gravity feed cookers are, but I would assume they are all similarly priced. If there is a big difference in pricing, I would wonder why.
I have used both lump and briquette. Briquettes burn more evenly, I'm sure do to consistent size compared to lump, but they create more ash. Briquettes are also better if you get a straight chute cooker as opposed to tapered.