Since you appear to be asking me, I'll answer.
The Bears need speed. I think Smith is faster.
On top of that, I'm not as sold on Cobb as I am on Smith. Cobb produced with Green Bay, where, let's be honest, just about any decent WR can put up stats. They have an incredible QB, a consistent system, and complimentary receivers that draw attention. Meanwhile, Torrey Smith had a pretty good QB, but nowhere near Rodgers. And I can't even think of other Baltimore WRs, so you know Smith was getting the #1 DB every time.
Last, but most important, is money. Cobb will cost a ton. Smith will not.