I would go for the jumbo only because I don't have one but it really is your taste - did you try them on? Does one suit you better in terms of how the size suits your frame. Also, will you be carrying a lot of things? My next purchase will be a JUMBO.
Well, I have a vintage jumbo and a medium lambskin flap ... though both are gorgeous, I tend to use my vintage jumbo more since I carry a lot of stuff. So if you do tend to carry a lot, go for the vintage jumbo. That said, nothing beats the feeling of walking out of the boutique carrying a black Chanel shopping bag!