LinLai WE 300B or the LinLai Global Elite Permaloy 300B tubes ?

Seems like HR's preference for WE based as much on warranty as sq. I believe the Cossor brand LinLai are Asian market only tubes, certainly not the same as Elite or perhaps even their lower level North America exports.

As for warranties, assuming we need to use, the WE or EML are way to go. Based on sq AND warranty the choice becomes more difficult, if warranty issues never become factor then go with best sq. But then we have to take in account that warranty length likely correlates with tube life, you may have to replace tubes with lesser warranty two, even three times in the five year warranty period of WE tubes. And to make it even more complex, lets say Western Electric tubes don't suffer failure over five year period, but they measure only 70% or some lesser amount of new a year or two down the road, which means we're using a tube not operating at peak for whatever warranty time remaining. I'd like to see tube measurements correlated with operating time, but then different equipment may affect tube life differently. So now I'm really confused!

Above presumes warranties only cover failure of tube, don't cover accelerated wear.

SNS you're definitely on to something with the warranty specifics.  Is it tube-failure, or a certain level of spec degradation before they'd replace ?  Other than some type of appreciable sonic difference, unless you have a good tube-tester or know someone fairly close by that has how would you know ?  Sounds like a good question prior to purchase !  I'd bet they have run these things for 5-years+ and have plotted the degradation/failure curves !  

@sns 
"but then different equipment may affect tube life differently. So now I'm really confused!" 

This is true. Some 300b amplifiers are more gentle  (or tougher ) on the output tube than others. It depends on their chosen operational points (OP).  I know that my Coincident Frankenstein 300b SET mono blocks are a bit tougher on 300bs than some other amplifiers with more conservative OP parameters. 

This is one reason why the EML XLS has worked out so well for me. This is a very rugged and durable tube. After 5 years of heavy use in my amplifiers they were re- tested and the numbers had not changed hardly a trace from when tested brand new. Above all they sound superb in my amplifiers. Reportedly they have a 40,000 hour life span (I don't doubt this).

Caveat,  in my opinion some brands of 300b sound/match better in some amplifiers compared to others. Synergy is always a factor. 
Charles 

Yes...  There are a number of factors that affect tube-life.  Depending on the amp, some push the parameters to the limit, others are more gentle.  A testimony to EML if they can be used heavily for that long and still sound and test well !  I know with my BorderPatrol S20 EXD, the parameters aren't pushed to the limits, and I've had Sophia Princess mesh-plates last nearly that long.  I can tell though that the sound is not the same when putting new ones in and though the old ones still keep playing, there is definitely a notable sonic difference.  The tube loses dynamics, and sounds dull.  This is especially true of tube rectifiers !  

I've not been able to move past present Shuguang black treasures as PT in 300b mono blocks or as drivers in Coincident Turbo 845 because of warranty and durability questions. The Shuguangs expose every upgrade I've ever made in system, seem to be a decently high resolution tube. They're rugged, no failures ever over many years now, whats not to like.

Based on reviews and my experience upgrading various other signal and power tubes over the years I presume some of the tubes we're talking about would be an upgrade. Again, the EML and WE tubes seem to be the most durable, therefore, safest bet. LinLai Elite could be new top contender, I'd not expect any greater durability than Psvane. Recently I've been close to pulling trigger on EML, Charles, I know you've used the Shuguang in past, how would you compare it to EML? I'd expect higher resolution with the same modern sound as Shuguang. I'd hope for just a bit more romance, bloom in mids while keeping relatively tight bottom end. In fact, this is the exact sound qualities I'm looking for in any of the 300B's.
Does anyone else out there have direct experience comparing Shuguang Black Treasure to any of the other 300b tubes? As stated above, seeking a bit more mid range magic together with tight bottom end, wanting to stay in modern sound camp with just a bit more bloom and resolution.