I’ve tried the Sovtek M and 5755 combo from way back in this thread when Justin originally recommended it. I’ve also since tried various iterations of the 6p14p family.
The new production Sovteks are perfectly fine, nothing weird sounding about them. My favourite were the Tube Store’s 7189, which are cleaned-up 80s 6p14p-EV. Same tube as what’s in the link above I’m guessing. Such texture and midrange detail on those! Also tried earlier standard 6p14p, from the 70’s, with flying saucer getters. They are nice, they have a bit more treble detail.
Unfortunately I remember not really liking the 5755. It is very different sounding then any other tube; very dry sounding, it just didn’t sound realistic to my ears. I was wowed at first, because my stupid brain always thinks new and different is better, but I realized it wasn’t for me. Maybe I didn’t give it 100 hours. The 70’s Raytheon variant was super cheap back then too.