UPR has three hooks on the quadrant, gives you more adjustability there. At least the red one has a jam nut, that's another thing I like about the UPR one. I'd go with UPR, if only for the price - it's definitely good equipment.
I don't think you can go wrong with either, the UPR extreme series is more comparable to the Pro Motion. I'd use a stock cable with either, the adjustables are junk.
One day you will hear a pop.. that will be the stock plastic piece breaking.... I prefer the UPR piece but that might be because I am a dealer.. Most of these piece are all the same so price should be the main consideration once you look at both..