The build is very sensitive.
Cause if you stay against the target spell heroes you need to get 2 of first spell and max 3rd spell. Most of all it needed on mid lane.
Sometimes you can rush manta, abbysal and mkb without bf.
But this build is the best optional.
Desolator works with first spell, so if you play against armored heroes, desol is a good solution too.
Bloodthorn gives 68 damage, also its a good solution against clinkz, huskar and annoying heroes like them. But only as the last item.
Writh bands are very useful artefacts in this patch so they are must have in early game.