That's up to you. I've used them (H70 and H100) and can honestly say that they're as good as, or better than, air coolers I've used in the past couple of years. Those include the likes various CM models, Noctua's beastly offerings and a few Scythe coolers.
Air and Closed Loop coolers are both subject to the same ceiling - ambient temperature. Closed loop coolers offer lower noise, high performance and the absence of a kilogram of metal hanging off your motherboard. Air coolers are easier to install and cheaper.
I still use my custom loop, because my own machine is still X58 based (and requires more than just CPU cooling). When I upgrade, however, I'll probably be getting a 2x120 closed loop cooler - if I don't just re-use my current loop.