Mint color is far from being my favourite color, but its fresh and light, and I love when royals bring something diferent.
However I agree with Duke of Marmalade, this coat doesn't look like a maternity coat, at the front, the hemline gets higher, if this was to be for maternity use, that definately shouldn't happen. On the other side, I find the buttons quite cute and I'm happy that she used one of her cutest hats.
I don't care for the shoes, she never had interesting shoes, however she finally took a brighter color instead of wearing those black heels all the time, so I'm quite happy about it.
As for maternity fashion, Catherine sure has a better fashion than Victoria did, but Victoria rocked Eveningwear and so far Catherine didn't go out for an evening engagement, so no need to compare evening look, so Catherine wins over Victoria for me.
Even though I'm eager to see Catherine in a more spring/summer dresses or other kind instead of her repeating coats style, I understand that in the UK is cold. So as summer approaches, I'm extremely excited to see her in a more diferent types of clothes. There's no need to rush, she will eventually wear lighter clothes in the near future.