if you get Cunning Brilliance it is awesome, and that is what you should base it on...
also, from my lvl 12 Factotum from dispatching the message, I have 32 Int, and that gets me +19 or +20 pr something in Open Lock, even if I only have one rank in it, I have +20 to init, tripping gets boosted, LOTS of skills, grappling, disarming, bull-rushing, the list goes on...
It does even make the Factotum an awesome 3 level dip, and it is extremely good...
Cunning Breach is good against lots of things, but it is not that good, I suppose, but BoB is terribly misplaced.
I have built 3 Factotums, played 2 of them (and will start with the third soon), and all of them got LOTS of bonuses because of BoB