The Noctua NH-D14 or anything similar looking to it is as good if not better than any liquid cooler closed loop. They're also cheaper. Doing push-pull on the radiator doesn't add anything.
But really it's up to preference about which one you like more.
It has been proven that Liquid Closed loops do better under load. At idle of course it will hardly make a difference. Price to performance is better on most air coolers but like the ones you suggested are huge and most people's cases do not fit them anyways. It is up to the persons decision about what they want to do with what they have, but doing push-pull on the radiator does make a big difference. I have no idea where you got the information from that says it doesn't. Any test would disprove that.
In case anyone missed it.
You can overclock it. It's just that you can overclock a K version much more easy and it's able to get higher clocks.
Poll