I just switched out my Genelec Gold Lion KT88's for a Psvane KT88's (on my Ayon Spirit II integrated)... and these are the differences... The Pvanes are slightly richer sounding, are more than slightly smoother (which is really important to me --- the piano transients and some clarinet and piccalo transients on the Genelecs were harsh, but not with the Pvanes), and the Pavanes are more relaxed sounding but still exciting. The image size, depth, and specificity are the same. The Genelecs were slightly more dynamic.
Overall.. the Pvanes are better in my system --- and since lack of grain and harshness matter a great deal to me, the Pvanes are much favored over the Russian tubes.