I had a couple of hallucinatory episodes using ativan (a relative had 1000s stockpiled, a few may have gone missing, here and there), on speed comedowns. In the two most extreme cases, tiny people swarmed all over my bedroom wall, and I unfortunately tried to explain this to my dad. Sometime later, I again dropped several wyeth lorazepam tablets after a long day and night on amphetamine sulphate, and a golden ancient figure in a loin cloth manifested in the room in front of me, laughing hysterically and pointing at my brother as we took turns on a bong.
I finally gave up on benzos other than valium, xanax and temazepam (or other downers), when I yet again gulped ativan on the way down from speed, but mixed with weird hash and a barbiturate, not, as I recall, one of the more potent ones. This time I saw eerie faceless bald women, and had a long, paranoid session of skulking in the basement till sleep FINALLY arrived.
Also abused them, free of stimulants, in my teens with booze, and had a few blackouts in which friends said I seemed to have been hallucinating, and extremely confused as to what the fuck was going on, but I remembered nothing whatsoever.
I always found them sickly, with a weird, not-quite-right feeling to the anxiolytic effect: they calm you down, no question, but always left me with a creepy sense that there was something VERY BAD I couldn't quite remember.
I feel a little sick just thinking about the fucking things. Thankfully, I haven't taken speed, and thus needed benzos, in couple of years.