I've had lots of experience with Chinese tube gear. In fact, I'm listening to one right now. I will say this. Most, if not all sound muffled and dead. The sound never seems to come out of the speakers. It's as if you placed a large drape over your speakers. Some are better than other but do not compare to US or EU gear.
They could be a diamond in the rough if you know what to look for and if you know a bit about circuitry.
Both my pre-amplifier and power amps have been guttered and the circuit redone with better components and a simpler design.
In my case, I wanted to build a 845 single ended amplifier and decided to get one from China as a starting point. It was cheaper than getting the parts separately.
There are sites that talks about these modifications such as Tone Lizard and others. But if you're like most, your dealer is right on his recommendations.
Good luck.