I once ordered McMurray's All Heavies Special, 25 heavy-breed cockerel chicks, it came out to about 50 cents a chick. I didn't notice any difference in taste/texture between the breeds. The main concern is how soon you can get them big enough to butcher. I processed those birds between 16-22 weeks, a few each week. Each time I'd chose the biggest-looking/feeling birds. There was an assortment of breeds ready each week, I didn't really notice a big difference as to which breed was ready first. You could try an order like that to see which breeds you like best.
The benefits to raising standard breeds for meat is that they don't have the health issues many Cornish Xs can have, they don't eat as much per day (although you do have to feed them for a longer duration, the amount may almost even out), they don't poop as much, and they don't have to be butchered all at once, but will wait for you to have time.