On the negative side, mine took 8 weeks to arrive. It shipped from China (I wish I had known that when I ordered it, I would have ordered from Amazon).
I upgraded to the 6P tubes. I immediately ordered the Voskhod and 5654Ws. Tubes were waiting until the amp arrived. I rolled to the 5654W. It took some effort to open and switch the jumpers (I only did one jumper at first, then found the other later). This did improve the sound. Given the difficulty of switching tube families I will not be switching back to the 6Ps, but the Voshskod and 5654 are in the same family, and easy to “roll”. I also own the AAA789, but this seems as clean, and there does seem to be a bit if a “softness” on the edges of the tubes from this hybrid.
Pairs really well with my headphones (HD6XXX, HE400i). Overall, a very solid amp!