I've been running the SD-Black for the past 4 weeks since the season began. After gettting it adjusted for my driving style, I love the way that it handles. I have broken 2 arms, bent one inner front hinge pin and broke the front shock tower.
I find it very easy to work on. Removing the diffs is a breeze. Someone else mentioned the fact that the A arms are all the same.
I considered the CGM, but honestly I don't think that having that chassis will make me any faster, besides it wasn't available when I bought my SD.