I prefer to use infinity for bosses. CB at 40% is great for merc to take out bosses. Merc damage is way better with infinity, so is his leach. IIRC ubers are over level 100. So skellies will have a harder time hitting the ubers, infinity takes care of this. So in my opinion more hits with a little less damage (but great CB, and lots more damage from merc) is better than a little more skellie damage and less hits (and nerfed merc damage, with 40% less CB) with pride.
I have tried both, pride is ok, but I am definately in favor of infinity.