Has anybody ever used these before, and do they really work or does the trolling motor still get tangles up.  Are lake is extremely weedy and we would like to prevent having to clean off the pro so much

Sharpening your TM prop blades slightly will help. I've never tried one of those before. 

Those basket style weed guards were old school and basically caused more problems than they were worth.  In very slight weed growth, they kept most of the weeds off - until one strand stuck and then it would act like a weed magnet and catch a bunch of weeds.  Down time while you cleaned the weeds off.  The chopper style props found on current Minn Kota & Motor Guide trolling motors eliminate the need for the basket.