soft > hard, nickel > titanium > kanthal.
so far not much diff, nickel are usually clean from the roll whereas titanium you need to clean with IPA. Do not dry fire either, if you can't help it set at low wattage to dry fire. (typically you'd want to do spaced coil rather than contact so dry firing makes no
sense either)
I have yet tried my titanium wires yet, will try to update when I feel like building one