I've had the most recent bout of PCS symptoms since 2004. I also had an shorter bout where most of the symptoms went away where the injury was in 1998 and the symptoms faded dramatically on their own in a few years.

The most recent concussion would probably be termed 'moderate', with only a few seconds of greying or blacking out after impact. However, the symptoms from this concussion are more dramatic, with the following symptoms

*Concentration issues
*Dyslexia when writing or typing
*Issues forming coherent sentences or speaking verbally (loss of vocabulary, etc.)
*Headaches (these are fortunately getting a lot better and are few/far between)
*Feeling of pressure/'congestion' in the back of my head, at the base of the skull/beginning of spinal column (nothing has shown up on any x-rays or MRI about vertebrae being out of alignment or any soft tissue issues. This also tends to occur more with headaches. I also have borderline-to-high blood pressure, which I'm sure ties into this symptom somewhere)
*Inability to deal with being in large groups of people-I'm almost agoraphobic
*Depression and anxiety issues
*Radical mood swings
*Easily irritated/extremely short temper
*Extreme inability to deal with stressful situations-at some point where the stress level reaches a certain point, all sorts of things begin misfiring. Something seems to take over on a fight-or-flight-instinct level and I just physically leave the situation. Naturally, this has caused a lot of problems, and has cost me one job, one relationship, and has repeatedly strained friendships.

Overall, I've had some symptoms improve, but overall things have been steadily declining.

I share a lot of the frustration that the other posters have with the medical community's reaction and treatment- I remember doing a lot of online research and took a bunch of printouts to the doctor when I first got treated, and the doctor actually TOLD me to my face that I was more well informed and knowledgeable about PCS than she was. Her treatment, rather than refer me to a neurologist, was to tell me that I'd have these symptoms for the rest of my life and to prescribe anti-depressants (Xoloft, which did absolutely nothing and I have since stopped taking them).