1) They say it's not habit forming. That may be true. But I intended to take it during the week, when I needed it most. On the weekends I wanted to stay up a bit later (not crazy, midnight versus 10pm. However, if I didn't take the ambien by 10:30pm I'd start to get a vicious migraine, that first weekend without it was miserable. I took it for a couple more weeks but the same thing happened each weekend.
2) About half the time it had no impact on me. I was wide awake and concious the entire night. Not able to focus well (entirely unproductive), but awake. I'd even eliminated caffeine by this point in an earlier (and ongoing) effort to counter my insomnia. But if I took it at 10 and hadn't fallen asleep by 11, I knew I'd be up until the next night.
3) When I did "sleep", there was a 50/50 chance I'd wake up with abs that felt like I'd been doing crunches all night long. I don't know what I was doing. I felt rested, but man was I sore.
I continued therapy and quit grad school in efforts to deal with my anxiety, and only after that was my insomnia properly dealt with. Which is a reminder, treat the condition not the symptoms.