I assume you are going to order cockerels. They are usually less expensive than pullets or straight run and give larger carcasses. That's the way I do this.
What traits do you want in a meat bird? If you are going to pluck them you might want a white or buff colored bird. Some pin feathers get left behind when you pluck and a light colored bird gives you a prettier carcass than a darker bird. If you skin them feather color doesn't matter.
Some people prefer a white, yellow, or darker skin though for a lot of people it doesn't matter. Do you have a preference?
Do you have a preference for light or dark meat? Most dual purpose breeds give a larger percentage of dark meat than the Cornish Cross hybrid meat bird. The true Cornish breed that was used to develop the Cornish Cross hybrid has a large percentage of white meat compared to most other dual purpose breeds.
How important is early maturing and size to you? Brahma or Jersey Giants eventually get really big but you may need to wait an extra month or probably more to take advantage of the potential extra size. Many of us prefer early maturing so we don't have to feed them as much.
Before the development of the Cornish Cross about 70 years ago, the most common breeds raised for meat in the US were Delaware, New Hampshire, and some strains of White Rock developed for meat instead of egg laying. Hatcheries have not been breeding them for meat for about 70 years so they aren't significantly better than other hatchery dual purpose breeds but if I were buying from a hatchery I'd look at them really hard.