I can hopefully shed a little light on this one, Justin.
Cart Mitts from FJ and Titleist are similar. Titleist is waterproof whereas FJ offers a more water resistant play. I believe they both have that warming "fleece like" liner on the inside.
6 to one half-dozen the other really. I personally have the FJ ones in my trunk now. But if the conditions call for cart mitts... I may stay inside and eat chili!
Can't go wrong with either, obviously. Depends on what you're looking to spend/elements of play