The lowland form of truncata has been in cultivation for decades, and is very common. It has basically green pitchers and the peristome varies from striped to red. It is found below about 800 metres and grows well in true lowland conditions, although it tolerates highland conditions (but will grow very slowly if it is cool)
The highland form of truncata was discovered fairly recently, and is much rarer than the lowland form. There is also only one vendor who sells it wholesale (Borneo Exotics). Highland truncata, in my view, is much more spectacular than the lowland form. It is highly coloured, varying from orange, red to purple and there's even a rare black form. Its peristome is more prominent than the lowland form, and there are a few other morphological differences. All round, it is far more attractive than the lowland form, and appears to get a bit bigger than the lowland form as well. It is found at around 1,700 metres, and needs highland conditions - Rob Cantley has some in his lowland house and has said they don't fare well at all.
Due to it being new to cultivation, its scarcity, its attractiveness and the fact that all plants on sale at a retail level have been imported, it is much more expensive than the lowland form.