As others mentioned, something based on sphagnum is the universal Nepenthes mix; I combine it with orchid mix and pumice for aeration, differing amounts depending on plant needs. Are the "stems" brown, woody things, or green basal shoots? If the former, who knows where they need to be; if the latter, they'll eventually push past the soil line but better to have them above the surface. If you intend to fertilize the plant, best to keep solutions within the pitchers; the "leaf" portions won't absorb it as readily, and if it gets in the soil it will be used, but the soil will often grow algae and break down faster.
As for this hybrid: should be bomb-proof, and I kind of want to acquire one at some point because it should be very tolerant of temperature and humidity swings and various light levels.