RG-11 is a larger sized coax. It has a 14 awg center conductor and more foam. It is good for longer runs and less signal loss. It is a little large to connect directly to a tv jack.
I have honesty not seen any better results with quad shield cable in my area. Quad shield cable is best in areas where high levels of RF interference, EMI, and other noise.
I think in most cases unless your just set on very best and most expensive when doing an install, your wasting your money.