Okay, so I've gotten through with uploading the video (Balancing robot issues - 2 - YouTube).
As I'd said earlier, the motors have a little bit of backlash, and then to add to it they're underrated for the size/weight/torque of the frame. So precise balancing and holding a position is out the window for now.
But, apart from that, the bot does hold position for very small inclinations/error.
I'll probably have to retune the PID constants(they're hardcoded in the video).
Also, I'm thinking of using steppers to control the robot (These: http://www.explorelabs.com/stepper-motor-68-oz-in-400-steps-rev ).
This guy has done an AMAZING job with steppers:
