Cryo Treatment: does it provide improvements in sound or longevity?

I'd be interested in hearing from audiophiles that have actually tried Cryogenic treated tubes and listened to them vs non-treated. 

I would really prefer not to hear from folks from a theoretical point of view, or that have no experience.

The last time I bought a set of tubes for my amp, just for fun I got the Cryogenic treated ones. They are replacements on my Audio Research Ref 160s. My KT150s were approaching the end of life and I heard them getting hard sounding. So I switched them out. The new tubes immediately restored the amp to its beautiful normal sound. I heard no difference from Cryo... although if it was subtle... no way I would... this was no purposeful comparison. I guess I'll have to wait 3,000 hours to see if they last longer. 

Just wondering if someone with good equipment and a trained ear has done listening tests (not measurements) and made a conclusion.