Ritalin can be a wonder drug for people with true ADHD. I was able to complete 2 college degrees, backpack through Europe twice, go on one extensive trip through England, and get a job that truly involved my skills and abilities. Not because Ritalin speeded me up, but b/c it slowed me down, without dulling my senses.
I got up to a very high dosage and in later years developed a tolerance even to that dose. I started playing pill games and taking outrageously high doses which I would have to compensate for by going without later. Very unpleasant addict games, I came to realize. So for once I did the responsible thing and discontinued the Rx.
So by all means, benefit from the med, but watch out for the temptation to self-adjust the dosage. If you really need Ritalin, you'll know it because it will really help you sort out your thoughts and organize your life.

Mike
PS -- And yes, there is a big anti-Ritalin crowd. Not sure whether any of them actually have ADHD, though!