I own a messenger bag and the weekend bag from these guys.  They know how to build a bag.  During the week, I load the briefcase with whatever I can fit in it. The harder you beat it, the better it looks.  I am not 100% sure, but I think you could load it with shot puts and it would hold up just fine, longer than your shoulder anyway.  Oh, and I have not mentioned the many many many complements I get on it.  It just looks GREAT.  It's only draw back is it's price, but I look at it like this.  I am 41.  I have owned and destroyed four briefcases.  Each cost between 50 and 100 bucks.  The math works out as I expect this will last a long long long time.
Well done saddleback