I went to the doctor and asked for Ritalin once during college and I found that I used it just like caffeine -- I'd be extra focused for a while on getting things done and then I'd realize I was staying awake way later than I planned. But I'd be tired the next day, and so the Ritalin seemed like it was more of a stimulant than a treatment, with one pill equal to about 10 shots of espresso.
I never refilled the Ritalin prescription -- it was no fun being medicated and staying up late and then being tired the next day. I noticed that I was far better at doing mundane tasks that required focus, but FAR less curious and less prone to switching tasks if I was bored.
Notably, I read tons of linux man files at the time and learned how to use a lot of command line utilities that I'd never had the patience to learn before.
But I'd also find that I'd read articles that were actually quite boring and upon finishing them I'd regret wasting the time.
There are a lot of occupations where my Ritalinized state would be an advantage. But one thing I love about my current approach to life is that I am able to leverage my own strengths. Sometimes being a bit scattered is a huge benefit. I also get the "hyper focus" common to people with ADD and there are days when 4 hour chunks go by as if they were 10 minutes and I realize I've accomplished incredible feats of productivity (and yet I remain energized).
Once in a while (maybe once every 2 weeks) I have a very scattered day. I have come to appreciate those days as good opportunities to restore balance. I use them to do extra exercise, eat extra healthy food, pick up the guitar, take an afternoon nap, etc. They are my brain's way of telling me that it wants a change of scenery.
I also find that regular, vigorous exercise and a bit of caffeine in the morning is far more effective than Ritalin was at giving me the ability to avoid being too scattered.
The best insight (which I actually learned from a comment here on HN last year) is that when I do find myself procrastinating it's my brain's way of telling me that I'm not happy with some decision I've made -- maybe an approach to some code, etc. So I use it as a cue to revisit what I've done and most of the time sure enough there is something lurking that was bugging me, and once I address it my productivity is back to normal.
Bottom line: I view mild ADD as a huge asset. I am extremely productive and while I have not yet managed to achieve my desired level of financial success I think I have plenty of ability to get done what I want to get done and tremendously enjoy the creative process and focused work involved.
One issue for me: I find that caffeine makes me physically jittery and muscularly tense. I wonder what smaller doses of ritalin might have done for you (or might do for me)?
I do recommend trying them, at least to satisfy your curiosity... and some people really find them helpful.
One thing I should also mention is that I've found that other aspects of diet seem to correlate with ADD symptoms. Getting plenty of exercise, taking an omega 3 supplement, drastically reducing sugar, and eating a fair bit of leafy green veggies are all things that I attribute to helping me focus more quickly. There are probably some websites/books dedicated to this topic, and it might be worth exploring.