Combat knife: Oh yea, I kinda forget those lvl4 weapons that are available only via long quest or from bio MvPs. The knife itself is a good addition for "defensive" Meteor (the one where you need more reductions than hitting power, like when facing sacri pally), but it is purely defensive weapon. Ice pick is better for Meteor/DD/SB.
I didn't mention Ice Pick for SBK, because I consider SBK almost purely hunting skill. Yes, it is extremely effective IF you have full time Bragi. But only then, and you will then be bound to role of "fire support". No hunting down of lone enemies, no empbreaking, no assassinations of precast chars...kinda lose most of fun from playing SinX. If you want to be bound to this role, go ahead, take it. But using IP for hunting only...what a waste.