My experience with Rudistor amps is that they have a high level of construction quality, solidity, pristine fit & finish, giving me no impression of cutting corners. From these pics & others I've seen online, I assume this amp follows suit in that regard. Sonically, I've liked most of the models I've heard (save for the budget balanced NX-33). I deeply miss my "lowly" NX-02 which sounded great, and a whole lot like a baby RP010. But I like Ultrasones too, so take from that what you will. Although the OTL RP7 I heard at a meet sounded great with Sennheisers.
Unfortunately, Rudi's amps don't present the best value quotient for those of us on this side of the pond. And due to lack of distributorship in the states, they have even less exposure to most of us here. Rudi seems to market more heavily to the European & Asian geographic areas, for what I can only assume are accessibility reasons.
Dual three-pin balanced connectors are more-or-less the standard set by Headroom from the Blockhead days. I'd guess there are more dual 3-pin connector balanced cables on the market & already in people's hands than the 4-pin type.
I can't comment on amp circuit or power supply design choices. Of course, anyone looking to spend that level of cash should audition first.
