I have to admit that I'm pretty impressed with my 4D-X. It is the copper version with low output. I've had it for just over a month now, it replaced a low output UNIverse with silver coils, which I owned for 4.5 years. I was expecting this to be a step down, since I don't have the $$$ to spend on a cartridge now that I did in 2005, but I feel like it's a lateral step instead. The copper 4D has better articulation and extension, the silver UNIverse was a bit sweeter in the midrange.
FWIW, my 4D is mounted on a Basis 2500 Signature table with Vector 3 tonearm, phono stage is a Klyne 7PX5.
FWIW, my 4D is mounted on a Basis 2500 Signature table with Vector 3 tonearm, phono stage is a Klyne 7PX5.