Flashed vs non flashed ESC's!
This subject seems to be surrounded with much conjecture and mystery which is simply not necessary or necessarily true.
When a DC motor is started it takes an amount of time to go from zero rpm to the desired rpm. This is the ramp up slope. Older DC brushed motors / controllers uses a low angle slope so it took longer for the motor to reach full speed once it received a command to speed up. This low angle allowed the current required to reach speed to be maintained at a low limit
Brushless motors add another variable into the mix and that is, since they are actually 3 phased motors, the phase angle and relationship between the rotating magnetic field that drives the rotor and the actual rotation of the motor need to remain "locked" in step with each other.
All the High speed ESC firmware does is assure that the above condition is maintained while increasing the ramp slope towards vertical so that the motor reaches the commanded speed as quickly as possible while maintaining the current at a level that is not in excess of the component limits the ESC.
Bottom line is a High Speed ESC responds to inputs more quickly whether issued from the Operator or from the Controller which translates to quick response and better stability because of the quickened response.
It doesn't matter if SimonK wrote the new firmware or if a manufacturer wrote it. If the parameters of safe high speed operation are adhered to by both writers the ESC's should perform similarly.
This is of course a gross simplification of the details. If you want in depth discussion then you will find it in all its brain bending glory here"
http://www.rcgroups.com/forums/showthread.php?t=1513678
Thurmond