I have had the exact same problems as you. My motors on a recently acquired "RTF" new to me quad would spin up past full as soon as I touched the throttle. It flies great now but it had a rough start.
Try lowering the motor output to 1600(not 1900). For whatever reason, probably the so-so Gartt motors that came with mine, the quad will oscillate badly if I increase the motor output to 1900. It's still set to 1600 and I am fine with it, I am not racing after all.
Also, make sure your artificial horizon is tilting the right way. It was opposite to what I thought it should have been and was incorrectly making attitude adjustments to change this to look like what i thought it should have been. Oops. These two things were keeping my quad from flying with a completely default config. Instead it would do cartwheels across the yard.
Of course what has already been said still applies; badly out of balance props won't help things either. I had badly balanced props too because they probably got bent up in the box. This did not end up being my issue but it didn't help things either.