I have some Freedom Rangers (now called Colored Range Broilers) which are over 2 years old and doing fine. They just finished their molt and look fantastic. I have probably 8 of them from various crops over the years, as I always grant clemency to the nicest looking hen in each crop of broilers.
The largest broilers I have made myself were breeding my Dark Cornish rooster to the freedom rangers. They were significantly larger than any other standard breed crossbreeding I did.
However, you do not get the heterosis you do in the original broilers and by no means are they equivelant. Whenever you are rebreeding hybrids the results are random.