I took delivery on a Cowboy 4500 this weekend. I was able to get it set up and running with only two phone calls to Bob. Amazing. This thing is a beast. I have been putting everything I can think of through it, including several thicknesses of leather with heavy knitted fabric (think rug - I'm making a bag), and it just chews right through it - no problem at all. It is just a pleasure to sew with this machine. I can't keep my hands off it! I'll post some of my creations soon.
I know there is a raging debate on this topic, but as far as I'm concerned, you can't go wrong with a Cowboy from Bob Kovar at Toledo Industrial Sewing Machines. No affiliation, just a very happy customer.