I love them both!!! If it's going to be a bag that get's tons of use - go for the Caviar. Everyone's right about this. I have both, and my lambskin one is reserved for fancier occassions!!!! The Caviar flap is for everyday use.
my SA at saks showed me how delicate the lambskins are when i was trying to decide between the two. She showed me a brand new lambskin and it was already damaged on the inside flap (because of pressure from the chains) and then she picked up a caviar and scratched it continuously with her nails, and it was fine! so i decided to get caviar.
The Ultimate SOft is different though, the finish is not the same as the Classics.
I think it's Golden{?}, she uses her's almost everyday and it's great. It doesn't wear like the other finishesx apparently.