My dad uses both the cast iron and aluminum DO's. I have one of his 12" cast iron, two other 12", a 12" deep, a 8" and 14" cast iron. Love them all. One is a lodge, the others are all the older versions, no names on them. They have the three legs, flat lids w/ edge around the top. I have used my 12" in and on the oven/stove at home as well as on numerous outings, camp-outs etc.
The greatest thing about a DO is that whatever you can cook on or in a stove/oven you can cook in a DO. Don't just use them for cobblers, they can cook a great loaf of bread. I've even used my lid to cook pancakes, eggs and french toast. One of my buddies cooks pizza on his lid and will cover or invert the bottom of the DO to use as the lid.
Use your imagination when cooking in a DO, they are a lot of fun. Pick up a book or two, keep them seasoned and NEVER, NEVER, NEVER use soap to clean them. Except when cleaning for the very first time. I haven't used one of the pre-seasoned ones. But if you're looking to stock DO's, Lodge and Camp Chef would both be good ones. Stock a variety of types in their line up the 12", 12" deep, 14" and 14" deep would be most common, but if they have them I believe the 10" and 16" ones would sell well also. I'm not sure they make the 8" one anymore. But that's a great one for sauces.