first off: thetubestore.com customer service is OUTSTANDING! they are reliable, and highly ethical in their transactions. I had mixed experiences with The Preferred Series 7025 tubes. One was bad immediately; one went microphonic after very light duty usage. Jon sent me 2 replacements. So far, one sounds quite good, the other sounds even better: fuller, sweeter, nice balance of bright sparkle and sweet lows. I'd give the best tube a 5 star rating; because of inconsistent tubes, I rated them 3 1/2 stars overall. Modern tubes can be inconsistent. that seems to be the current situation. In any case, I will buy from thetubestore.com for future purchases again. Integrity counts.