I've raised three batches of Cornish Jumbo X-rocks. They mature fast, but I really don't like raising them. On 9/11, I received my 1st ever batch of Colored Rangers from JM Hatchery. I'm really impressed with the ordering process. I didn't really like using PayPal, but the chicks were delivered within 1 week of ordering.
I can already tell that these birds are different than X-rocks. I like getting my chicks on dirt/grass as soon as possible. In the past, when 1st put out x-rocks, they didn't move much at all. But when I put out the colored rangers yesterday evening, they were all over the place.
For the way I raise chickens, I think the colored rangers are going to be the best bet.