It's an acute benefit though, isn't it? I've noticed that people coming down off of amphetamines are not as productive as they might otherwise be.

Probably, it'd be hard to say for sure. I personally don't take it every day and sometimes just take half of my dosage, to reduce tolerance. There definitely is a tolerance though and also a bit of Yerkes-Dodson law type deal at play, e.g. if I take to much I am also not productive.

I would definitely say it increases my productivity output though overall.

They could beat you in their productive phase and suffer while coming down. Lose-lose.

Do you know of an acute performance-enhancing/experience-enhancing drug that doesn't have a shitty come-down phase?

That's true, but meth mouth is a particularly shitty side effect.

Correctly dosed and this isn’t an issue