I also disagree that N. ampullaria is ok in highland conditions... I have tried and it hates it!
Yeah N. ampullaria is not good for true highland conditions. But it does well in intermediate conditions. My grow-room is usually 60 at night, and 80 during the day, but gets down to the low 50s at the coldest point in winter, and I have three different amp varieties growing well for years now.
For lowlanders, they are pretty tough.
Warm to hot conditions. As far as I know, more humidity helps in speeding up the plant's growth and increasing the pitcher size. Another thing is the light intensity. It appears that the basal rosettes or small young plants prefer it shady. However, when it vines, it can take strong sunlight like any other nepenthes.