Like a lot of the people here, I get excited when I hear of new bags, but I make the final decision when I see the bag in person. While I get attracted to popular bags, I know I wouldn't buy a bag that I didn't love no matter how popular it was.
I have both the fendi spy python and the green lambskin and I ADORE both. I love the size, the quality is really first rate (my problem with the Chloe bags is they don't appear perfect in the small details). For me, the fendi spy would appeal to a slightly more sophisticated, perhaps older target group than the paddingtons and silverados.
If you are worried about longevity, I think the spy will not be a seasonal It Bag the way the paddington is turning out to be. And if you want Chloe, I would definitely choose the silverado over the paddington.