I don't know if it compares to Ambien at all, but my wife takes that and every once in a while I take one to help get to sleep. It gets me to sleep and I stay knocked out, but a long 8 hour sleep with Ambien never seems as good as a "real" 5 hour sleep without it.
Ambien drastically reduces the restorative deep sleep and REM phases of sleep, so you are correct in your assessment. Your brain needs those phases. Long-term use can cause cognitive issues and cancer.
