I've found mixes with too much sphagnum (lfs and sphagnum are the same - there's also LIVE sphagnum) tend to pack down and get slimy over time. I still use it in smaller containers as it does hold water well, but mixed with half chunky bits like orchid bark or pumice. As I start moving my nepenthes into larger pots, I switch to a chunkier mix with no lfs at all. It's about half shredded cedar mulch (cheap in big bags from the garden store), well rinsed, and half other chunky bits like perlite, pumice, or charcoal or fir orchid bark. This drains better, and in the larger pots doesn't dry out too fast. Nepenthes like open mixes where water can move over the roots.
Capslock