A while back I purchased one od the DJI F330 kits with esc's and motors. I had a NAZA control unit so I used it to play around with. When I would fly the quad I would notice when taking off the right front was always lazy about coming up. It says you can't do anything with these esc's but the unit was just not too stable it was flyable but just not fun. I put my APM 2.5 on the unit, used save trim and got it flying very good. I noticed that when powering up the motors did not come up at the same rate. I flashed the esc's with BLHeli using the flash tool from OLLW's site I used the file for the Plush 18a which went very well. Got a chance (dry day) today to check it out and it flew great. After using save trim again. I would come off the ground almost like being on a vertical string. I put the NAZA controller back on it and this time it flew like it should no lazy right front. The flash tool is neat you can flash all 4 motors at the same time. I used a Arduino Mega 2560 to flash them with. I know in most cases these esc's work just fine out of the box but the ones that I got were not very good.