I checked out the compressor as well as I could before purchasing and eventually decided against it. Not because I thought it was any better or worse than the Omega Turbo Charger. I talked with Jason, the sales rep for GX and he assured me that their compressor and the Omega were VERY similar, however ... the fact is that they do not have a service center in the US. The servicing goes something like this according to Jason ... they do offer free replacement parts and they need the end user to supply the details about what is wrong with the compressor including videos (if necessary). Then their supplier, the factory who makes the compressor will judge the problem and determine what happens next. Jason says the obviously this will be a little slow to solve the problem, also not so accurate. But for our small 12v compressors, there is almost no this kind of unclear problem if buyer provides the details. For GX E-5K2, actually this is a second generation and we have not heard quality problems, they performs very well until now.
Personally, I would have had no problem buying the compressor if they had a service center in the US, but I have had experience with the Omega brand, both the Air Charger and the Super Charger and the odds are excellent that at some point within the life of the compressor you will have to have some kind of service done ... especially for folks like me who are not all that mechanically inclined and the idea of trying to explain to someone in China who probably doesn't speak good English, exactly what has gone wrong with a compressor when I don't know myself. Well, it just doesn't give me a lot of confidence.
As far as the compressor goes, it is probably as good as the Turbo Charger. In fact, the advertising says that the two pistons are sufficiently independent of each other that if one were to slow down and even stop working, the compressor will continue to produce pressure with the remaining piston, but at a slower rate than normal.
I am not saying that it is a bad compressor, but any and all compressors will need servicing at one time or another. If you are a good mechanic and can analize problems common to compressors and re-build them yourself, then more power to you, however I am not so blessed.
Shalom
John