Z-drugs are also referred to as "non-benzodiazepines", as in "drugs that do not contain a benzodiazepine ring, but affect your GABA receptors in pretty much the same way that benzos do."
Zolpidem ("ambien") is more selective for certain sleep-inducing subunits of the GABA receptor than the vast majority of benzos (which is presumably why it seems to cause dream-like hallucinations and euphoria in some patients), but once tolerance builds, there is little difference between ambien and a plain benzo, except for ambien being much shorter-lasting than the average benzo.
The other popular z-drug is zopiclone/eszopiclone (sold as "imovane" and "lunesta"), which lasts slightly longer and is less selective in its action on the receptors than zolpidem... in other words, it is virtually identical to a "real" benzodiazepine, except for the shorter half-life.
Lastly, there is zaleplon ("sonata"), which is even shorter lasting than zolpidem, which means that there should be a reduced chance of hang-overs... of course, there is also a good chance you might find yourself waking up in the middle of the night and having to redose.
That said, improper use/abuse of (non-)benzodiazepine type drugs is a dark path to go down... these substances tend to be corrosive on people's personalities, and the first thing they lose while they're on them are usually their redeeming qualities.