OK, so maybe I'm just old and cranky. Or maybe it was the 30+ hour flight that just carried me from Houston, TX to Hong Kong. Nonetheless, after biting my lip many, many times, reading replies to this identical question, on a few different photo forums, I have slipped passed the point of prudence, and must offer a response. (Just this one time... I promise never to do this again).
Let me do so by addressing a statement in Ian's posting - "I've also handled 2 or 3 Fotoman cameras and there's nothing really to distinguish between them in terms of quality etc".
Simply put, this statement is simply erroneous and therefor misleading.
Having been involved in the manufacturing of highly engineered mechanical products (of many types) for more years than I care to recall, allow me to point out just a few differences between our Fotoman cameras, and the Gaoersi offerings, which I would think should be easily observable... even upon a cursory side-by-side inspection;
Viewfinder - ours utilizes an advanced (multicoated) optical design, which exhibits far less distortion than the Gaoersi. Our VF is lightweight, uses easily interchangeable, precise, light weight, low cost Masks, and sports a bubble level which is viewable both internally and externally. The Gaoersi VF is very heavy and very inaccurate. We know... embarrassingly, we actually packaged the Gaoersi VF with our very early cameras (for a very short time). We had so many complaints, we offered an at cost upgrade for over a year, to make amends.
HFM - our Helical Focus Mount is truly a thing of beauty, if I do say so myself. It's buttery rotational feel is the result of a 6-start, fine pitch helicoid thread. The Gaoersi HFM utilizes a single high pitch coarse thread, just like a screw, which results in a rough, imprecise feel. While the rough feel can be masked, to some degree, by a generous application of thick grease, this will lead to problems of high torque when subjected to cold temperatures or migration (read: mess) at elevated temperatures. Additionally, last we checked, it appeared as though the Gaoersi HFM utilized the same distance/DOF markings for several different focal lengths.
Internal Coatings - rather than a simple flat black paint for the interior of our Bodies and Cones, we use the identical anti-reflective coating Nikon does for their cameras, which greatly increases the contrast of the recorded image. When you consider the internal surface area present in a 617 camera/cone, the last thing you want is unfocussed, contrast robbing light rays bouncing all over the place.
There are other differences, most of which have to do with the quality of raw materials, and may not be observable upon a cursory inspection... so I will not detail them here. Suffice it to say, that when a proper grade of raw material is not obtainable in China... we source it elsewhere.
In the end, perhaps one of the most gratifying testimonial to the difference in quality level, comes from previous Gaoersi owners, who upgrade to our Fotoman cameras. And while I can offer no proof positive to validate such, I sincerely doubt the reverse is true.