I tried the uberman schedule about 18 months ago and only made it about 10 days, including several oversleeps, then went back to everyman, and am now back to a normal monophasic schedule. My ability to nap robustly within 20 minutes has persisted to this day, which I still make use of when tired. I was not able to do that before experimenting with polyphasic sleep.
My friend and I are starting the Uberman sleep schedule (six 20-minute naps spread evenly throughout each day) tonight. Have other lesswrongians experimented with alternate sleep schedules? Are any of you qualified medical experts who can give input or advice? Success stories and failure stories would both be appreciated, and I'll keep you guys posted on our progress.