I asked this just about a week ago. Hard to source is one reason you don't see more of them. Coupler is more expensive new, but pretty cheap on ebay used. Coupler is also taller, which could be an issue for some, but Perlick makes a low one, but good luck finding one used, new they are $55.
I have one I am planning on using for my HERMS HEX. If I could find more of the 1/6 sanke, I'd used them in a heartbeat. I think cleaning might actually be easier once you remove the spear. Just use one of those drill operated carboy cleaners and you can go to town. Can't really do that with a corny because of the beer tube, but I think that's removable as well if you really wanted to.