I just bought the electric blue Mahala last week. It's my first JC bag (first designer handbag for that matter) and I am still convinced I am insane for spending this much on a bag. However, I LOVE it! I love the shape of the Mahala, but I fell in love with this blue even more. I think the bag is the perfect size. I am 5'4'' but I like to carry a big bag. Personally, I think the Maddy is too small.
As for the color and daily wear, I think it goes with a lot. Blue is my favorite color, and I feel that a lot of the clothes I have in my closet are complimentary to blue (even if they are not blue themselves). My best friend has a fashion design degree from FIT in NYC--the best fashion school in the US. And she said she would carry this bag with any outfit. And she always looks put together, even if she doesn't exactly "match." I do love the plum color, but I was told they aren't carrying that in the US boutiques. If I get another Mahala, I will get the black with gunmetal hardwear!
As for those who are concerned with the "season" and specific colors for certain months of the year--I say boo hoo. JC just decided to carry this bag over for F/W so I am using it all year long! Oh, and I always wear white after Labor day.