Pixhawk is good, but requires far more involvement that DJI to setup and tune.
I will also attest to that.
I have Xaircraft SuperX on low KV quad, (started on x8), and Naza V2 which has been on small quad, large quad, and now my x8 w/ low kv motors. No problems with them other than I didn't like the SuperX on the X8. No fly aways or crazy loss of control issues on either.
I have a Pixhawk on my test (550 ) quad now. It takes a lot of time to learn. I've had 1 small crash with it while flying low and in Loiter (GPS) mode and it was because it loses altitude in GPS mode more so than my other FC's.
This past week, I tried a quick grid flight on the Pixhawk (my first autonomous) and it flew the 3 minute pattern as I programed it to. It came back to the start point (RTL) and came down about 1/2 way. It paused and I switched out of auto mode to stabilize (I think) and within 2-3 seconds, the copter shut down and came down with no power. I have sent the logs to 3D Robotics to see if they can tell me what happened.
I'm not writing about the failure, but just that in my research before buying the Pixhawk, I sort of expected a few more crashes or episodes of "what happened" because of the increased features and general nature of open source software. This past one happened on a first try on the autonomous flight but also after recently using 2 switches for 6 flight modes which is harder to keep track of then just 1 3way switch for flight modes.
I'd say go for it, but expect a fair amount of time learning it and I'd suspect more crashes than you have had to date with your other FC's. The one thing I don't like about the Pixhawk is the way they connect the wires. In my recent crash, my quad weathered the crash with just 1 broken leg a very slightly bent arm which was easily fixed. However, my GPS puck pulled off the arm and 1 cable pulled out of the GPS puck and the other pulled the wiring socket off the circuit board of the Pixhawk. I now have a Pixhawk with no gps connection.