When I first read the spell, I thought, hey cool, I can get the Viks up to CB 10 on their swords. However the +3 bonus only kicks in after you've hit, so really it is next to useless. Compare this to the straight +2 damage.

If my combat total was 0, +2 damage is going to do at least 5 damage (5/6/8 damage range), +3 combat total means instead of -- damage flip I just have - damage flip. Minimum damage is 3. It gets worse from there. At all other initial combat totals, the +3 is not enough to guarantee moving up to the next range as the ranges are 5 points in total. Straight damage is almost always better.

The only time I can see the +3 combat total being good is when you want to cheat damage and want to increase your chances of being able to do so. However, even then you are most likely better off with the +2 damage just because the minimum damage with +2 is only 1 less than the max damage straight. So I'd say, always use the +2 damage. 3 Paired Strikes with 5/6/8? Now I see why the Viks are called glass cannons!

What about Jokers?

The Jokers really play with the odds in Malifaux, often in counter intuitive ways. If both Jokers are available, you are overall better off with + flips because you can cheat and you pick the best card, unless it is the Black Joker. So if only the Black Joker is available each extra draw you make is increasing your chances of pulling it. This is particularly bad on damage because once you get to the damage flip, often all your opponent can do is take it. To pull the Black Joker at that point really hurts.

Likewise, if only the Red Joker is available, even -- damage flips are good as you are increasing your chances of pulling that Severe + damage. I am sure I could pull out my rust stats skills and work everything out, but it largely depends on whether or not you can count cards effectively, a skill I don't have