Just finished putting together the ZMR250 kit and working through calibration in LibrePilot - it seems that even after ESC calibration, the motors are are starting at different values. Some fire up and spin reliably as low as 1025, while others don't spin continuously until 1050+.
I've re-run the calibration a few times to see if I can get the values anywhere closer, but have had no luck.
I decided to set the values for each motor to the lowest value that would make them spin continuously, complete the configuration and then test the quad to see if the gyro would kick in and help to level the quad - this resulted in many cartwheels and several broken props (ouch).
Would be very grateful for any help troubleshooting this - I'm unsure if I should be suspecting the motors, ESCs or the CC3D itself!