O ring chains cost so much more and I haven't noticed any difference. I just buy a mid quality non o ring chain - about 65 dollars -- and use a spray on chain lube.
Sure, I get A LOT of fly off, but I am not exactly concerned about keeping my clothes clean while riding off road.
I do not race and don't ride too often so cost isn't too big of an issue for me in terms of re-applying chain lube.
When a standard chain streches out and the tighteners are all the way out, I can use a chain breaker to take a link out of the chain and move the tighteners back in and get a bit more life out of my chain.
Trying to take a link out of an o ring chain is a nuisance.
1986 YZ 250, still runs strong