"If your footage suffers from rolling shutter effect (distortions or image wobble) after stabilization, this is a problem inherent in your camcorder's CMOS sensor. Mercalli exposes this weakness. You can now eliminate this effect by enabling the Rolling-Shutter Compensation option in the Virtual Stabi-Cam area."
Well, in my experience only the first part of the above is true: when stabilizing with the Rolling-Shutter Compensation option unchecked for the test purposes, I'm getting lots of diagonal warping and tearing, not at all present in the original footage. So indeed, "Mercalli exposes this weakness".
Unfortunately, checking the Compensation option removes it only partially. What is left is still more visible than before stabilizing! So it does work, but not good enough, sorry.
Even looking at the samples provided above I agree, the results are not acceptable. That's not to say Mercalli is not doing as good a job as can be done, just that the problem cannot be fixed in post. Some may well find the outcome acceptable or be faced with no other choice. In that case Mercalli is excellent value for money, $200 doesn't buy much when it comes to reshooting a scene.
On the other hand if the outcome is useless spending $200 to get a useless outcome is money better put to doing it right.