I had a GX 450w some time ago. It worked good enough to power pretty low end system. Overclocked, stable and for a long time (athlon ii x3, 2 hdd and nice hd 6850). It is even working in another computer that gave to a friend. I guess that theses guys will just do the job, way better than the Extreme series.... which are crap.
Prices will have to be better on the "street" for these to sell. When Corsair has comparable PSU's around $40-60 street (sometimes less w/MIR's) these will have to be similar to get any traction.
Iirc, the GX-450 was the only GX that reviewed well; the others were not good at all. Unless these are made by Seasonic, I will assume they are poor, unless / until they receive favorable competent technical reviews.