acid is WAY harder to have a bad trip on then mushrooms...
i had one relatively unpleasant experience that was still a good one... basically iw as fucked up out of my mind and my friend was even MORE fucked up, he took like 9 hits of acid... Anyways, he was kind of annoying me from how crazy and irrational he was being. a third one of our friends got in a fight with a homeless guy at 711 and it was just all sorts of chaos; not stuff you want to be dealing with while trippen...
ur chances of having a bad trip while u are in ur "comfort zone" are VERY VERY small. Unless you are mentally weak. I say take it, relax, and have the time of ur life.