Update... I bought a Menik SQ-600 and SQ-1200 from mkstudio2012 on eBay. They were both dead on arrival; the big discharge resistors had been sheared off the PCBs and were rattling around in the cases; it looked like severe trashing in transit or maybe some very clumsy assembly work. They *look* really good and solid, but they don't work. They're currently on their way back to China to be replaced by (I'm promised) tested-working ones.
Score so far: 0 for me, -1 for Menik/Suncy QA and/or China Post and +10 for customer service (if they do as promised) from Meking Studio (eBay reseller) as they're going to make a huge loss on this sale due to shipping costs.
The SQ-600 has about 500J of capacitance in it and the SQ-1200 seems to have about 800J, depending on what voltage they charge up to. I have my suspicions that the SQ-1200 I received was actually an SQ-800; it has the same PCB as the SQ-600 and more capacitors are loaded, but not all of the footprints have capacitors in them. The power and control PCBs (and cases) are clearly common between all of these flashes, they're just loaded out with more or less capacitance. I noted that the 1200 had a different tube from the 600, so hopefully they're properly rated.
So they're lying on the specifications, but not nearly as dramatically as some other Chinese vendors I've seen where the actual power can be as little as 25% of rated. Interestingly (I had a good look at the PCBs), they're wired for about 600-800V (pairs of 300-400V capacitors in series) instead of 330V, which should make for reasonably short flash durations.