I've been using them for the last 2 1/2 years. They are strong and durable. The quicklink that I've used that came with them is only used to connect the chain. Once connected you'll need a chain tool to disconnect it again. I use an SRAM powerlink to connect and disconnect the chain. In my opinion KMC chains represent the best value for the money and are in fact better quality built than the best known brands out there. YMMV.
I've been using the *mart KMC $6 chains off and on for the past few years on single speeds or internal hub bikes. No complaints except that the heavy duty model is a bit noisy. I've had no problem reusing the traditional master link, though it's probably a different design on the shifty model.
I'd spend the extra four bucks and get the silver Sram. They're nice and quiet and shift well. I don't doubt that the Nashbar chain is good and am curious to how it is compared to the Sram.
> Once connected you'll need a chain tool to disconnect it again.
Actually, the 'quicklink' may be removed and re-installed. Simply squeeze the pins of the link together with a pair of needle nose pliers. I wouldn't do this too many times as this wears the retaining nubs - although, under tension, the link will not come apart without breaking.
I guess I will try the Nashbar KMC 9 speed chain. I ordered the recumbent chain. $15 less 20% is $12. 232 links. So its $6 per chain for a standard bike.