I bought the very clone amp you asked about a few months ago and I hasten to say that it is beyond a doubt the most superb amp I have had in my system in 50 years. I paid pre-tariffs $750 for it delivered to my doorstep. It out performs my Don Sachs KT88 amp and my Wells Audio Innamorata amp. Check out the myriad reviews on the amp... it is truly the real deal.
Is it a perfectly representative of the original DarTzell amp, now off patent protection, that I can't say. But the fit and finish of the amp belies its modest cost and more importantly, it is by leaps and bounds the finest amp I have ever had in my system.
At my ripe old age, I never thought I'd have such a phenomenal amp in my system.