Like Buttercream, I would rate Crave to be 3.5. The cakes are decent, though not legendary. It's the icing that's absolutely fab though. One thing though, the Red Velvet was a bit of a disappointment, as the cake really had some off aftertaste that no amount of cream cheese icing can fix entirely.
Being the first mini chain to bring the cupcake "craze" to Calgary, I have to say that they did a fantastic job from the start. Even now, its not unusual to come in duing the mid afternoon and find them sold out.
Now the 17th one has shut down for unknown reasons (probably due to the high rents of the street and the competition of Buttercream just down the road), but the other outlets are still running strong. Still, well worth a visit if in the area.