Just found this thread. I have raised the Cornish X several times. Last year I bought 50-50 Cornish X and Red Rangers just for an experiment. I made the processing appointment for the Rangers 4 weeks after the Cornish were scheduled to be processed. When I took in the Cornish X, I thought it couldn't possibly be worth it to feed those Rangers an extra month. Guess what? IT WAS, from the first bite. The Cornish X make a bunch of meat fast and it just doesn't taste anywhere near as good as the Rangers.
This year, we are breeding Marans and Marans X Barred Rock sexlinks. The Marans are a heavy breed and we have lots of extra cockerels. The first of them are being processed next week, and from what I've heard we are going to be happy with the results. They are good foragers (unlike the Cornish X who have to be practically carried outside away from the feeder) and appear to be growing very well. The Marans X Barred Rocks are growing heavy fairly quickly as well, but they are younger and won't be processed for a while yet.
Raising our own meat costs more than buying the shadow of a chicken from the store, but less than buying organic from the store. I know where they come from, what they ate, the conditions under which they have lived, and how they are ended. The taste is so much better than either purchased option and I'm certain healthier. The humans in this household are worth the cost and labor involved.
PS: No one has yet spoken to the cost of electricity (but I didn't read all 13 pages). In NW Oregon, each heat lamp running costs between $15 and $20 a month. Raising 4-5 brooders full of chicks in the winter has really opened my eyes to the cost of the electricity.