Yes I have. The ZYX Live 18. It was used on my Ikeda 407. I have also used a Dynavector headshell, an original Ikeda headshell, and finally a Yamamoto Ebony Headshell. The ZYX was my favorite for fit, and sound when I did the comparison. It is subtle and might be more related to changing the effective mass of the arm/cartridge combination more than anything else. It could also be tonearm cables. Too many variables to know for sure. Basically, I recommend it but it is system dependant. I needed an additional headshell at the time. A few people I know who have tried it indicated that it they liked it a lot as well.
From memory, bass definition improved, treble extension improved and detail increased. Also the attack and timing was slightly more live. I compared it to the Ikeda headshell w. the ZYX Universe X-SB. Now I have a Jade in it.
In my system I didn't like the Yamamoto at all. The Dynavector headshell seems very good as well, but doesn't fit my Ikeda as well.