First of all, let me say that I'm not that experienced with Ambien, I've only done it 4 times.
Yes, I did get visuals (at around 20-30 mgs), but they weren't kick-ass visuals like an acid trip. They were more subtle. In closed-eye terms, I saw swirling colors and burst of light; in open-eye terms, it seemed as if bright lights projected themselves (like 3-D). For instance, after about an hour of taking 20mg, I looked at my alarm clock and couldn't read the digits; they were projected and it seemed as though the digits were dancing / sliding back and forth.
In terms of addiction, I can see why people would want to abuse it, because visuals are cool and because it's fairly easy to get from doctors (I've yet to understand the "no possibility for addiction" thing yet; it's a Schedule IV). Personally, though, it's not something I would want to do regularly. It made me very lethargic, and, after staying up a while, it gave me a really bad headache.
Also, I know Ambien isn't a "true" psychedelic; it's a non-benzodiazepine benzodiazepine. But, since your question pertains mainly to hallucinations, maybe you'd find more information in psychedelics or trip reports.