My two main gripes about the professional bag are: (a) the shoulder straps are place too far out and a fully loaded bag sort of slips past your delts (I prefer my backpacks to fall in the little indentation between the traps and the delts, and (b) the zippers are almost impossible to operate with one hand (an absolute must when riding city buses and subways).
The pluses: Color (I bought a black one) is great as are the general aesthetics of the design. I especially like the computer compartment that suspends the computer a little above the bottom...for those times when you forget you're carrying your computer and drop the bag a little too quickly on the floor.
For those who care: The name "Nixon" unfortunately is a little too visible for this survivor of the Watergate era. (Maybe I have a "Clean for Gene" patch I can sew over it.)