I have considerable experience using this sleeper before flights. To be quite frank, I didn't really research the drug very well, and sometimes cut the time down to about ten hours before report. We were working very hard and they were a life-saver for a string of ‘earlies', as I'm naturally an 02:00 to bed person and can fly all night with no problems at all.
This was a bad mistake on my part, especially after my feelings about related drugs. But as you say, there seems to be no after effects...but there was for me...eventually.
Having turned up for a flight, time and time again, feeling clear-headed and full of enthusiasm at 05:00, I felt that as flying is a very good indicator of one's mental agility, there couldn't be much wrong. However, some time later I was retired and going through a very difficult time. Insomnia was just one of the trials that I was faced with. This drug always solved the problem, but...now I was using them as a prop (say 3 times a week) and something was going terribly wrong. As I have mentioned before, an example might be standing staring into the fridge wondering why, only to remember that one is looking for a Black and Decker drill! Under the circumstances it was difficult to determine wether it was psychological, or caused by the drug. I determinedly resisted its use, and improved markedly after about a week. I ran the experiment again about three times over the next year and it was always the same.
I am a very small sample and the experiment was without ‘controls', but I'm pretty sure of the results.
I found that simply having the drug at hand was a help...an escape route if you like. And even if I did give in, I would break a tiny amount off the end of the tablet as try that. It usually worked.