The cable chop sounds great on paper, but when it comes to the execution it's less of a core exercise and more of an arm blaster. Also, the resistance changes drastically from beginning to end.
With this method, the Swiss ball acts as a cam similar to what you'd find on a machine, giving you the feel of constant, equal tension throughout the ROM and putting that tension right where you need it.
I'm always experimenting in the gym. Hell, I sometimes think if I didn't spend so much time trying new ways to train that I'd be a lot further ahead, physique-wise.
If you've only been training for a couple of years, just about anything you do in the weightroom will make you stronger. However, those of you who have been training a bit longer need to pull out the heavy artillery.