The EHX 6V6GT it's a very good tube, able to provide a very rich tone and a notable lifespan, with a very consistent performance all around.
While used on clean, it shows a tendency to scoop the mid range a bit, providing a thick bass and a glassy high range; all this without resulying in any kind of muddiness whatsoever.
Overdriven, we can appreciate a fantastic harmonic richness, and a great dynamic response, with heaps of sustain if pushed for good.
Putting a classic overdrive such as the Ibanez TS808 makes it really shine.
I personally use it on an Ibanez TSA15H head, and am very happy with the overall performance it gives.
Definitely recommended.