I took the DISC assessment recently. I was not impressed. I'm high D. The end product was a list of recommendations about how I really need to invest more in empathy, especially with certain types of touchy-feely people. Ok, I don't argue the truth of that, but I knew it already. No big surprise there. I'm sure DISC is useful to some folks, but the grade I got on it pretty much just said, "You're a jerk." and "Stop being a jerk." It was probably productive, but I rejected it's conclusion out of hand, so it felt like wasted time.
I had a completely different reaction to the Myers Briggs evaluation. I ran the test last week. I fit the INTP mold in a very pronounced way so I did some reading about it. Until then, the best label I had for my odd combination of behaviors and traits was 'manic depressive', which still might be true, but doesn't explain the whole picture. I was shocked by the several documents linked from INTP.ORG. They all seemed to describe me so completely and objectively, far more accurately than I could do myself. The articles about INTPs I read all told me real and useful things about myself.
After consuming all the articles I could find online, I found this forum so I could learn about myself and see what other INTPs did with their self-knowledge. This looks like a nice spot to roost for a while; interesting people, mostly polite, and _very_ unusual conversations.