Doug Deacon's review did not say the Universe was "decidedly" better than the 4D. Instead, the essence of his post is that the 4D (also known as the Atmos) might be preferred by rockers, and the Universe preferred by classical music listeners. He also wrote that he could see jazz lovers preferring either cartridge, depending on listening taste.
https://forum.audiogon.com/discussions/review-zyx-atmos-x-sb-low-output-cartridge
I own a 4D. I am very pleased with it. My next cartridge I think will be a Universe II or Universe Premium. I would be skeptical about getting the Ultimate version because of reasons stated in this thread.