Kalug a is a bespoke implementation of Hypex NC1200 module
They are great and considered among the best in D class design with enough amperes to drive most complicated speakers including ML.
I have heard same module, with top of the line Weiss Op Amp.
I have decided for Purifi 1ET7040 im the end (variable gain option)
Compared to other amps, the cost of those is very competitive. 400 watts at 8 ohm and then just about doubling at 4 ohm is nice. I'd be willing to try them out if I needed new amps. So far I've always been class A/B, but my mind is open for D.