Modern Day 6CA7 Tubes

Has anyone played around with using 6CA7's instead of EL34's. I've heard that the NOS Sylvania 6CA7's are wonderful, but now there are modern ones made by EI, Electro Harmonix, and (I believe) SED/Winged C. The Sylvanias are hard to find, but the modern ones...? Anyone have any experience with these?

I'm using a pair of Cary SLM-70 monoblocks, each takes 4 EL-34's.

Thanks, Peter
i was using the EH 6ca7's in my Jolida 202A before i sold it and found them to be a great impromement over the standard EH EL34.They provided very nice gains in the mids with no losses anywhere else in my system.I believe they were a gold brand but not sure anymore.Yeah i liked them a lot!
I have tried the EH 6CA7s and prefer them to the Svetlana EL34s. The bass is much better and the midrange seems smoother to me. The overall sound is smoother with the bass, midrange, and treble blending better.

I just go some Elctro Harmonix EL 34s and will listen for a couple of weeks and see what I think. Then change out the 12AX7(Tung Sol, and Phillips) and see if any combo with the Elctro Harmonix EL34s sounds better than the EH 6CA7s.

If these EH el34s don't do anything for me I am going to try some other brands of 6CA7s. Besides the ones listed above are there any other brands of 6CA7s?