I think you need to be more specific about the payload and length of journeys you want to do, and how often. By reputation the TB-20 carries more, but bear in mind you'll be paying £15 per hour more for fuel every hour you fly it, to do a few knots less. Over a year, that's a lot to pay if you only intend to use its extra hauling capabilities once or twice. Even with an 860 lb useful load, our Mooney will carry 660 lb for 3 hours with VFR reserves.
The problem with published useful load figures is that they don't reflect reality, sometimes being optimistic by 150 pounds or so on a sensibly equipped several-year-old aircraft. Check any particular aircraft before you buy it if that's important (get it wieghed).