Strattera is an atomoxetine. It works differently than the traditional Ritalin because it's not a stimulant, and affects different brain chemicals, yadda yadda yadda...

In my experience, it doesn't make you gain weight. I supppose it works, though (and this is just my experience) I found that while usually it made me oddly "contained" (calm, etc.), on random days it would suddenly stop working and my ADHD would come back 10x worse for that day, as if all the ADHD-ness that had been suppressed was suddenly being released.

But yea that's just my experience. I stopped taking it a few years ago (only because I felt I could do without it, not because it wasn't good).