Kashmira, I was just like you, very hesitant about sanguine. I thought the color was amazing on swatches but was somewhat worried about how it would look on a bag...and to be honest the picture of the birkin above didn't really ease my doubt on whether I would like it or not. I'm not really a pink person per say, nor red for that matter and that picture shows sanguine as a pinkish red (at least on my computer).
Well I was lucky enough to be offered a 28 kelly retourne in sanguine at a store this past weekend and just fell in love! I had always said to myself that I wanted a color that popped if I ever got a Kelly because my style is so casual, its not ladylike at all. When the SA showed it to me I knew I had to have it. It definitely had a more orange-ish tone than that picture suggests but I do think its a chameleon like color, the lighting will definitely affect how it looks. I will post pictures once I receive the bag, which should be today (I had it Fedexed to me). Hope this helps!