The current FP helis fly identically to the FP Piccolo. Stability comes from proper setup and component selection.
Now if you are going to step up to a CP machine like the T-Rex or Blade CP, then there IS a stability increase.

Yes, parts are going to be less well distributed, but a quick search on the web showed suppliers.

As for a comparison between a single rotor FP heli like the Piccolo and a dual rotor heli like the co-comanche, there is no comparison.
The FP Piccolo is a very difficult heli to fly. Robust, but difficult to fly. Once you have learned to fly a FP micro, you can fly anything.
Co-axial, counter rotating helis are so easy to fly, many people find them boring. They virtually guarantee success, but do very little to prepare you for flying other helis.