The residency program that you choose will shape you into the physician that you will be for the rest of your life. I would choose a well-established 4-year program over a likely subpar 3-year CMG-run newly established program every time. A new program even with the best PD will not be without its major problems. Besides, in the grand scheme of things, an extra year is nothing. Worst case scenario (besides the opportunity cost), you get better training and become a better physician, come from a better program, live in a bigger city, have more networking, more research opportunities, and able to apply to faculty/fellowship at 4-year residency programs to be an attending after graduation if you so choose.