I've been trying it in Asia with Cathay Pacific's Asia miles. I don't really do card churning, although I've opened a few cards just to get the sign up bonus. I only have two credit cards that give me a good cash to points ratio, and I try to use them to make the best out of it. For example, one I mostly use when spending money abroad, just because I get a better ratio on foreign transactions. While the other one I use for all my daily transactions, I hardly ever use cash, and all my payments are linked to this card. I sometimes also take advantage of some of the restaurants deals they offer. It also helps that I use my own credit card when making expenses while on business trips, this has probably earned me a significant amount of points.

All in all, I've been able to redeem a few flights, and upgrade a couple of long-haul flights. I'm not that obsessed with it tho.

There's an Aussie site on point hacking etc https://www.pointhacks.com.au/