Being brand new to this forum - I am aware of this reply being very old. However - I think this question deserves some further scrutiny from a little broader perspective. First -- good design is good design. Period. The Fendi Spy is amazing design without question. Second -- you really need to ask yourself if this bag (or whatever item you are considering - bag, shoes, dress etc.) fits well into your overall sphere of personal style (assuming you have taken the time to truly contemplate what your personal style is --- many don't). If you are in the affirmative on both of these questions - what more is there to ask? The ability to listen to your inner voice is beyond critical in all questions sartorial.
As for my experience with the Spy bag specifically, I recently bought my first two. After an exhaustive search, a significant amount of research (verifying authenticity) and some creative budgeting - I was able to find the perfect fit (on both). Both bags were previously owned and I felt confident I was purchasing items that were well cared for by their previous owners. Both are in immaculate condition and were purchased for a very fair price. Having mused my first two questions above at length - the Spy is a harmonious addition to my sphere of personal style. They're just gorgeous. Period.
Oh -- and one last thing.... I love them, and that is all that matters.