I was going to mount the twin (on my TJ) but it wouldn't fit where I wanted to put it, so I got the single - best compressor I've owned and I've had a few over the years.
Space might not be such an issue with a JK - I've seen plenty of clever twin mounts on JKs.
Only issue I've had with my CKMA12 - had to replace the relay and now I carry a spare relay, just in case