1) What is it? The info I find online is mostly marketing/promotional stuff so I am not going to believe that.
Plenty of research can be found on what it is. It is your blood spun down with Acell injected to help produce growth. If you want the science behind it, it can be found easily.
2) Are there brands? If so, which are the best/worst?
Not brands, but the Angel System seems to be the gold standard right now for spinning down the platelets.
3) Is this a skill in itself i.e. are there doctors that are better in it than others?
I think that there is a skill to it, but I think that the protocol is the most important. Dr. Cooley probably has the most results to show.
4) Side effects?
That is a question for a doc, I know that itching for a while seems to be common. Also, shockloss has been reported as happening.
5) Is it a long-term solution?
It is a long term repeatable treatment. If it works for you, like finasteride, it may always help improve your hair, but that does not mean that your balding can't overtake the benefits. I have seen mixed reviews on its effectiveness from being close to nill to being mind blowing. I think your fist round is a roll of the dice to see if it helps. If it does, you can use it as tool until something better comes along.