I have a Greco folder and a Greco fixed blade.
In my experience they are some of the finest working knives produced.
They are not shiny, and they are not perfectly finished and precision machined. They simply provide a large amount of cutting performance for a comparatively small price. I also do not have any of the A2 knives, but the 8670 ones that I have take a very nice edge. A2 is a highly regarded steel, and I have never heard any complints about the steel performance of CRK's fixed blade.
I did find that I had to scuff up the micarta handles on my fixed blade, as they were quite slick at first. Just breaking the polished surface a bit made a dramatic difference.
From what I have seen the Grecos are as good as and in some ways superior to other "hard use" fixed blades that cost far more.
The fixed blade I have is one of the flat ground models, and it seems to be a good general thickness. Thankfully it does not maintain full thickness to the very tip like some knives do, but instead thins out gradually.