I've tried modafinil a few times. It helps me a little with alertness, but not much - I can use it for long drives, but it didn't particularly help with programming. I sometimes get a side-effect from it that makes it something I can't take at work: I get super cranky and easily angered, like shouting-argument angry. It's out of character for me, and really weird.

I took piracetam for a few months, and I thought maybe it was helping my focus and short-term memory. The side effect of that one, though, was even weirder: recovering sense memories of being a little kid. Like, flashbacks of the physical pain of the first time I had a bad injury. Vivid recollection of my adult teeth pushing my baby teeth out of the way. Even sensations of being an infant with no body autonomy at all.

Worth experimenting with? Absolutely.

Magic bullet for superhuman productivity? No way.