Jay, I replaced a metal-base GZ34 with the EML in the PS for my Denon/Modwright 3910 early last year and thought it made a nice improvement in the high frequencies. It's all synergy, IMHO, and I kept a MB GZ34 in my Modwright LS36.5 preamp, finding two EML's to be a bit too analytical. I no longer use this gear, so if you'd like to try the EML, shoot me a PM.
Be advised that the you should verify that the EML will work in your particular circuit and that some folks over @ Audiocircle are experiencing early life failures (though the tube has a lifetime guarantee).
/Ken