Cup feeding has the benefits of easy food-intake monitoring and reduced escapees, among others. Free-ranging has the benefits of exercise for your animal and possible psyochological benefits by allowing them to hunt. I would say to mainly cup-feed unless you find some compelling reason not to (overweight, lethargic chameleon maybe). That being said, I cup feed but will occasionally place easy prey (silkmoths, sometimes silkworms and hornworms) in plain sight of my chameleons, this way they can feel like they're hunting and I can be pretty sure I'm not going to lose the bugs (The bugs I use don't typically move a lot or don't survive long enough to hide). At least one of my chameleons seems to appreciate the "hunt" if his fervor is indicative of anything.