Different things work for different growers. This is my experience.
Peat-Perlight:
Works best for VFT (they like very loose airy soil, cheap and easy to find. Moderiet to high water levels required. Look out of algea, I sugest a top layer of live sphagnum to prevent this. Bad for sundews, not sure why, just is, probubly because perlight chunks are too big and most sundew like heavier wetter soils.
Peat-sand: Best for most sundew, if for VFT, get really corse sand, I don't get very good root growth out of this in VFTs, but the tops get bigger insted which some people prefer.
Pure LFS:
Works best with water ubsessed sundews. Usually causes issues in VFT, for vft keep water levels low to moderiet. Prone to thick goopy algea in higher water levels and light, put a layer of sand over to to reduce this. Same issue with mixes, it's just too darn wet for most VFT and promote algea, but mixing in sand and or perlight helps if you need to use it. People in aired and hot regions tend to like this.
Pure Peat:
Depends on the individual VFT, some prefer the dencer mix, but it's the same issue as when sand is used, the root growth is minimized while top growth in increased. Better for drier regions. Wet loveing sundew sometime like this, but it can still get too packed down for them. I don't usually recomend pure anything.
Peat-sand-perlight-LFS:
Seem to like this okay, but the algea issues are still there.