Quad 4 processors in phone will come as early as Q1 next year by Motorola. Prepare for abysmal battery life. The Atrix was an exception for dual-core battery life only because it has the largest stock battery in a cell phone to date.
I believe we are still in Q2
Droid Bionic will likely be like any other Motorola...unstable as a man riding a bull with a jalapeno in its ass, but with specs to drool over. I have not played with a rooted Motorola yet (will be rooting my buddy's Atrix real soon here), so I can't comment on it's stability after rooting. I had HUGE hopes for the Atrix, and was severely disappointed by its performance.