Anyone tried using both of these Fables together before? What do you think is the best combo for this?

Killer Attack seems to only be on 2 blades: Live Axe, and Spear of Honor
Guard Parry is on 4 handles: Rapier, Dancer's, Cursed Knight's, and Black Steel.

I hate Guard Parry, but I do like feeling cool and using stupid things for fun, so I'm planning to try this out once I have time. As far as I understand from Google research, Killer Attack is easier to land and does more damage, but Guard Parry is cheaper and has more consistent timing. I don't remember if either one triggers Stagger or not.