Opinions on STR-425 5881 tone?

[GJgo]

Does anyone have opinion on Mesa's STR-425 5881 tubes?
http://www.mesaboogie.com/tubes/power-tubes/5881-6L6-STR-425.html

Tone-wise I'm mostly a metal player. Reading around I seem to hear real mixed reviews on this tube. Reason I'm asking is, my IIC++ DRG has the 105PT and it's running 515pv. This is Mesa's only tube that'll take that kind of abuse reliably.

I have old Sylvanias in it now which sound amazing, but when they wear out I'm not sure I want to pay top dollar for old used tubes that might not be biased right. Trying to research my options before I need them!

As far as new production tubes I've been pointed towards the TAD 6L6GC-STR, Tung-Sol 7581A, and Tung-Sol EL34B. I've never tried any of these.

Ideas / experience are welcome!

 

[igfraso]

For what I understand they are a little bit bassy and good for jazz.
When I asked Mike Bendinelli if I could use them in a Mark II-A, he said better not because the II-A was already a dark amplifier.