I didnt bother reading this whole thread, but allow me to share my (very recent) experience..
I recently built a repeater using two KG1000G's, a cheap mobile duplexer, a Tram 1486 on the roof and LMR400 coax - all the experts assured that my 'toy' would not work at all. Despite what all the experts predicted, not only did it work, it worked better than I expected, with a range of about 40 miles in each direction.
I have now got my hands on a (very) used Vertex VXR-7000 repeater - after paying for programming and re-tuning the internal duplexer, cost was about $650 - it DOES work better - less de-sense so it is noticeably more sensitive/able to receive signals that the KG1000g setup could not, and i'm getting a bit better range.. But the other big difference is that it is 'full duty cycle' so it can be used 24/7 - Wouxun says that the KG-1000Gs can also be used 24/7, but i'm not sure I believe that claim..
Was I happy with the KG1000G setup? YES! Am I more happy with the "real" repeater? Yes.
Do the math and do what works for you..Ignore the 'experts' as many dont seem to understand the difference between the term "will not work at all" and 'will not work perfectly/be the best" ...