Electro-Harmonix 6550 in ARC

Has anyone tried this 6550 in an ARC or other amp?
I'm getting ready to re tube my ARC VT 100. ARC currently provides the Winged "C" 6550 as the OE tube.
Both are available from the retail tube sellers.
I'm using the EH6550 now in my VT100 mkii. They replaced a set of winged C 6550s. Sound great to me...
I have tried both, but in a CJ amp. I like the Winged C better than the EH, just had more detail. Currently using the TungSol 6550, very good, balanced sound and tubes seem to last a lot longer than either the EH or Winged C's.