Ambien is probably the most awesome fucking drug that exists.... hands down... I love how 50% of people will completely agree with me and we could talk about ridiculous ambien experiences/stories all night... and 50% will tell me that I'm fucking retarded and "wtf why would you try and get high off a sleeping pill"
I know Tiger WOods know's what I'm saying... haha.
And in regards to your question: I have a lot of experience with both xanax/benzos and zolpidem... however, I can't really answer that... I have never really noticed a specific, notable difference on the effect of ambien when having taken a benzo with it..
I believe ambien effects a slightly different area of your gaba receptor, very, very similar to the mechanism of action of how xanax works - but different (obviously) at the same time. So, I think it really depends if you have a tolerance to benzos or not.
If you do - from personal experience, I really can't remember it ever seeming to make any difference.
But if you don't/have a low tolerance... then I think taking .5 xanax with it would just make you more "out of it" and perhaps cause more amnesia. .5 is not a lot of xanax - so I would go for it. Why not? Of all the benzos - xanax would be the best to take with it.
However, if I had both, I probably would just take the ambien. And take the xanax separately another time. I LOVE the effects of ambien, so I wouldn't want to "taint it" with xanax. But that's just me.
I really might co-author a phD book about ambien. What a fucking INTRIGUING drug.. seriously. I am kind of fascinated by it. For the percent of the population for which it seems to work this way with: euphoria, sometimes exhilaration, increased creativity, increased ambition, increased empathy, appreciation for life/small things, diminished/no anxiety, less inhibitions.
LOL everything BUT sleeping!! haha.
I would pay $100 to someone if they had a overall more EPIC ambien story-experience than I can claim.... All I will say for now is: 20mg Ambien + Scubadiving in the Galapagos Islands 1 mile off the shore + playing with a pack of baby sea lions + huge rare black aquatic giant Iguanas + mindblowing golden sunset + private guided diving boat = ABSOLUTELY SURREAL RIDICULOUS DAY
def on my top 10 list of experiences...