My experience is limited, but my understanding is Cornish x make the best fryers. They are what you would find at the supermarket. However, they grow so fast and so big that they will not move willingly. They will not range, not willingly. You will need to kick them out of the coop, and unless they are starving, they will find some shelter or brush and lay down not move. Do not ever drop them, they cannot fly at all, will probably break a leg (this was the mistake I made, I often just drop my layers they fly to the ground, Cornish x drop like a brick)
I do not know how they will fair with another meat breed as coop mates. I know my layers hated them. My two Barr rock hens beat the cornish cross mercilessly.