5y3 rectifier variations?

[Jimboshappy]

I've changed 5y3gt rectifiers several times in my Mesa LSS. With no other logic than NOS must be better, I have used eBay sourced Sylvania and Motorola tubes just cuz. So browsing TGP brings me to ask: " what should I look for in rectifier tubes? "

 

[Blue Strat]

Is there some sonic, or other, characteristic that you're looking for? I'm not sure what you're asking.

 

[Jimboshappy]

Is there some sonic, or other, characteristic that you're looking for? I'm not sure what you're asking.

Clarification as see how my op was unclear. I've only changed tubes when I fried one. I'm inquiring about what sonic differences I might expect to find, if any, amongst various rectifier tubes? Do you look for anything aside fr/ basic function in 5y3 rectifier tubes?