Has anyone here tried polyphasic sleep?

I'll concede this could be off topic, but I am curious as to wether anyone in this academia.SE community has tried polyphasic sleep schedules (sustaining a sleep pattern of more than one sleep per 24hr period), and if so what their experience was like.

I'm a PhD student and I am entertaining the romantic idea of the Uberman sleep schedule (20 minute naps every 4 hours). Freeing up an extra few hours of waking time every day certainly sounds appealing, though I imagine in all reality the health implications aren't great.

In any case, I would love to hear any personal stories if anybody has one.