I also got one just for kicks, since it is really not expensive...
As is unmodified, it is a bit on the clouded/muddy sort of sound, not very clear/sharp. It does have good punch, but it really need to work on the detail side of things.
I've so far modded the input tube to take 12AX7 instead of 6N2P (I don't plan to tube roll through all of Russia/Eastern Bloc have to offer, so 12AX7 it is), and swapped the Chinese FU-32 for a pair of RCA 832A. One interesting thing I found between the Chinese FU-32 and RCA 832A is that RCA's plate is like what you'd expect, uniform color, no scratch or other marks. While the plate on Chinese FU-32 was really scratched up, not that it scratched through the plate coating, but it was quite visible.
Other than the tube swap, I've also replaced the pair of coupling cap in between input and power tube. These cap is interested, as it uses ceramic housing, instead of the normal epoxy dip/plastic wrap. Perhaps it was some kind of surplus high voltage cap re-purposed as audio coupling. Since I have no idea how these if those cap are good or not, I swapped them for a pair of Bennic FPP 0.33uF/400V caps (It was 0.1uF, unknown voltage).
the amp is just back in one piece about 30 minutes ago, and I'm letting it warm up before listening to it seriously. By warming up, that include the irons on this amp, as they tend to get pretty warm after a while. Which does take a while. :P
Seriously, these tubes really light up pretty, especially if you dim the room a bit. That alone might be enough for quite a few people to get them.