I have never paid special attention to this amp, but it would have deserved it. To me, the best currently purchasable china cracker. Only by chance I once got one and was very impressed.
Clean construction, robust, with reverb and it sounds quite good in the standard version. If you only change the speaker (G8C) and the preamp tube (5751), it is already a great device.
Without having to remove the board and with very minor modifications, you can get even more. Remove C13 with the pliers, carefully - cut remaining contacts. And solder the two anode resistors over a 220k. Now another Elko with 22uF over R13, finished.
Now, the tone control is better to use and the amp also responds better. Of course you can put in more effort, but you don't have to.
I like this amp. In the league of 5W/8" there's no need to hide, that's for sure. Even with more expensive amps. Very highly recommended.
Apparently there's a new version of the device, now with SMD and a changed setup. Here's a picture of the circuit board. You have to look for the exact changes.