some considerations:
1) I think there are very few amps with balanced inputs at this price
2) the price/performance factor is scary. It would probably put it at the top of any ranking
3) I had a V3, taken for testing, and I admit that it was a really good amplifier, not at all intimidated even with quite large speakers. So this shouldn't be any less.
4) the only note: the system proposed by Fosi which makes it usable also as both a stereo and mono power amplifier, it seems fun, to experiment and play a bit, but leaves me a little perplexed: two or three potentiometers on the same line seem too many to me. I am afraid that the signal may have deteriorated in some way. I would prefer a pure power amp therefore without controls.
5) congratulations to Fosi for this line of products, which is essentially spot on for the price.