Given that 9+s chains have flush pins and thus countersunk pin riveting, it seems reasonable that some design limitations are being approached as chains get narrower; a quick link generally requires two thicknesses on the side plate... It appears that some folks can design a reusable quick link for narrow chains (if SRAM's is really just sidestepping a patent, they need to get the informal word out); if they work well when used properly, they're definitely preferable to anything else, IMO.

Having to replace a link or pin for cleaning is a bit sub-optimal; once the chain's started to show some wear, you're introducing an unworn pin or two, which is going to generate some additional wear on rings and cogs due to the slight discrepancy in effective link pitch. I know it sounds pretty anal to mention it, but given the sometimes drastic effects of very subtle wear on drivetrains, I think it should be noted. It's tempting to re-use an old quick link on a new chain, but if you can see or rather feel any wear on the pins with your fingernail, don't do it.