Here is a photo of the contour colours I use most often - depending on my mood!
The square blush on the left is Illamasqua Powder Blush in Rumour.
The round blush on the right is MAC Blush in Strada.
The depth of the colours are very similar, however the Strada has more of a blue or cooler undertone, where the Rumour is more neutral. There may be a tiny bit more light on the MAC blush, as it appears slightly lighter in the picture than in person.
This MAC blush is my very first MAC purchase, and really should be thrown away due to it's very old age - but I just can't part with it! I have heard people say that Strada has been discontinued, but others have said it is now available only in PRO stores. You'll have to check out your local MAC hidey-hole to see whether you can find it.