I'm not a tube-expert, so I can't give any technical information or details. I have bought this tube, because my powertube was cracked. You can read a lot of positive stuff about Sovtek-tubes made in Russia, so I decided to try it. The exchange of broken and new tube was very easy and now my amp works again. The sound is different, but everyone should know, that different tubes create different sounds. The Sovtek-tube is a little bit "harder" and in my opinion not as warm as the china-tube I had in action before. But I really like the sound. It pushes more gain out of the amp: i love it!
Pros: - not too expensive tube - perfect to experiment different sounds - good processing-quality