There are many pros to the spy -- it's a stand out, stylish yet classic bag, not to mention that it can hold a tremendous amount. Fendi has done a great job creating a bag that is of the moment and classic at the same time. It is an eye-catching and beutiful bag!
That said, there is one main con I've encountered with my darker colored spy. I have a brown spy bag that I bought almost a year ago, and it is *impossible* to keep the leather from fading.
I completely baby my spy -- I watch how I carry it to prevent any rubbing against me, don't ever let it brush against anything, never set it down on the floor, protect the leather with appleguard and apply apple's leather lotion whenever the slightest bit of fading appears.
Nevertheless, I feel like I'm fighting a battle I can't win -- you still notice that the bag is fading around the edges to the top opening and on the spy flap/handle, and there is also fading on the sides of the bag.
I haven't had the same experience with my lighter colored honey wisteria, and I have read on here that Fendi now treats the leather on the spy bag to prevent the leather from fading.