They're two very different airframes. They do not share any parts or construction methods, etc....Think of them like they are from two different mfgs.

The only thing they share is the (IMHO) flawed aileron mount method. The servos are mounted to the hatches. There's plenty of room to hard mount them to the wing standing upright, and there's no good reason to mount them the way Sig chose to....

The Cap is lighter, I flew mine on a Moki 180 at 12-1/2 pounds. It was pretty overpowered, but flew well. I even won pattern meet in sportsman class with mine when it had the original MDS148 on it. With the MDS 148, it was about 8 oz lighter and power was about equivalent to my buddies Sig Extra with the OS160. Snapped and spun like a Cap should, tracked well. I think it flew much better than the H9 73" Caps I saw flying...I'm convinced the airfoiled tail and almost 2 lbs less weight made the difference.

My flying buddy has the Extra with a OS160 at 13-1/4 pounds. The Extra is not overpowered with the 1.60 and the extra weight. Flies like an Extra, tracks very well. Early Sig Extras had firewall problems and later models have aluminum angle reinforcing the firewall attachment.

As for landing, etc.....They are both relatively high performance aerobatic aircraft and their takeoff, landing, etc...are not real different from each other. Depending on CG location either could be a handful to land or not.....

Richard