Update: The Z8RC design mods bring the mCPX to A+. Without them, the mCP X grade stands at F.
Winds have pushed me inside. This flight review will be different than most as I am only an advanced novice when in comes to flying RC helo's, but I think there is value in this kind of review too.
So far, this helicopter experience has been painful. The copter is reasonably crash resistant, with one exception: the feathering shaft which bends in mild tussles that wouldn't phase an mCX.
My suspicions of this build-quality defect were confirmed when I visited the official Horizon mCPX page and the usual sales video has been replaced with a feathering shaft repair video. Additionally I found a product bulletin (my local hobby store was unaware) grounding these helicopters until a dangerous rotor head defect is fixed. I don't know if the new head is stronger and better protects the spindle, but obviously they both provide and replace the feathering shaft in the repair video so that is clearly part of the recall.
I am comfortable replacing and connecting these delicate parts, but the vast majority of buyers need will want a professional to do the work. The provided Horizon Hobby "solution" (mailing out new heads and feathering spindles) is obviously unacceptable and results in an unusable purchase and thus a 100% loss for most consumers.
Overall Grade: F
Systemic quality defect with no acceptable solution.