https://medznow.com/ambien-vs-lunesta/ 

Both drugs are prescription non-benzodiazepine “Z-drugs” used in adults for insomnia. Ambien typically works faster and is better for trouble falling asleep, while Lunesta has a longer duration and may be stronger for difficulty staying asleep. 1 Neither is clearly “better” overall—effectiveness depends on your insomnia pattern and individual factors. Both carry risks of next-day grogginess and complex sleep behaviours (like sleep-walking) if you don’t allow a full 7–8 h before waking. Choosing between them should be done with your doctor, considering your sleep profile, underlying causes and other medications.