It has been five years to the first post, and the thread is almost dead now - but I am pretty sure there are a few of these SV engines still surviving. I want to add my experience for posterity's sake.
My first SV was a 26, exceptionally smooth and easy to start engine, not a powerhouse, almost the same power as a DLE-20 - but very reliable - I flew it for over 200 flights on a small fun fly before selling it with the plane. I bought another 26 on ebay, which was identically performing - flew that one for about 50 flights, then the plane crashed - the engine was sold separately later.
I bought a SV-52 twin on ebay, it was a repair project as someone had stripped the plug threads - repaired and flew it on a 85 inch extra for 80 or so flights. Absolute joy to run, first flip starts, never quit and about the same power as a 45cc RCGF engine - Sounds very good at idle and upto 4000 rpm. That engine was later replaced by a single in the airplane, and so it now resides in my display cabinet. It will surely fly many more flights.
I bought a SV-100 version 2 (or 3, as it has DL style cylinders) on ebay last year - It spins a Menz 27-10 at 6100, very smooth, very easy to start, and trouble free thus far - not many flights on it yet, so I will comment on reliability later. It pulls around a World models 36%, 29.5 lb (13.4Kg) Katana with ease, and has plenty of pullout from a steady hover. It has almost the same pull as my 3W-85CS.
video here
https://www.youtube.com/watch?v=Qu2Qi3fKDZ4
All my engines were originally sold by Khurri model engine works in Germany. I never had a single issue with any of these engines, so I would say the engines are more than ok for the price. The only engine I will not recommend is the 17cc single, which is disappointingly underpowered. They are reasonably well constructed, are certainly beefy and thus sturdy, heavier than DLEs and certainly have lower than average power for their size - but they make up for all that in price and ease of operation.
Where would I rate them - well DLE has marched so far ahead of the competition of Chinese engines, I think SV engines would only be a niche engine for the money concious - they are good reliable long-lasting engines, but they can not compete with the newer Chinese brands - (hell, even 3w and DA is having trouble keeping up with these new Chinese brands)
That is my experience with these queer little engines from China