I've had this bag for 3 years and after everyday use, i'm not easy on my bags, the zipper finally broke after that time.  I was heartbroken, my favorite bag.
It's sturdy, not water proof but I'd say it's slightly resistant.  (i've never been in a deluge with it)  The leather bottom, is HEARTY.  the strap is comfortable and switchable depending on what shoulder you want to use it on.
Can't recommend it enough.  If i had one criticism it takes a bit to get used to the length, and digging around the bottom to find that penny down there.  ;-)  However, that's a small con and I'm buying my second one now to replace the first one.