The two are so far apart in terms of, well, everything... I can't imagine the choice for your needs not being obvious. They're both responsive, nimble, great flying 2-seat side by side airplanes and both come from Van's. That's about where the similarities end. Two completely different airplanes for two completely different missions.
The 12 is a fine airplane if you are looking for a non-aerobatic, 110-120 knot airplane with very limited baggage capacity that's relatively cheap to fly (Rotax and mogas). If you need to go LSA it's the only RV choice, and arguably the best LSA choice.
The 7 is a LOT faster, is aerobatic, carries more, has longer range, can be built with a sliding canopy and/or tailwheel, gives you easy choices for different engines and props, and on and on.
I know I'll get arguments left and right when I say this, but the cost to build either one to similar levels of equipment is about neck and neck.