I would say there is definitely similarity between some of those fragrances, but there will be slightly different but noticeable differences in the scent purely because they have very different notes, when you look at the Joop and the origibal santal, I would agree there is something fairly similar about those scents and I like both but I still prefer the Creed, but as you say Vinny is it worth £100 more than the Joop? well that's very relative, the individual nuance within the scents may be the deal breaker.
Joop
Top Notes: Mandarin, Lemon, Orange Blossom, Bergamot
Middle Notes: Jasmine, Lily Of The Valley, Heliotrope, Cinnamon
Base Notes: Vanilla, Tonka, Patchouli, Sandal
Creed original santal
Top notes: Orange Tree Absolute, Jamaican Ginger
Heart notes: Lavender, Peppermint, Rosemary, Juniper Berry
Base notes: Sandal wood from Mysore, Virginian Cedar, Absolute Vanilla, Benzoin from Thailand, Ambergris, Tonkin Musk