Well the question can't be answered as it's asked. You see, different pieces of wood cut differently even if they are from the same sub-species. In fact they can cut a lot different even in the same piece of wood from place to place. That goes for Sugar Maple, Red Maple, Black Walnut, English Walnut, Bastogne Walnut, Cherry, Persimmon, Ash............and probably others too. No single type of wood is always easy.
Hard and plain is the easiest to carve. Fancy curl or grain makes things more difficult.
Too soft and it won't hold the carving very well unless the design is large and fairly "bold" but fine details need a dense and hard wood.
Inletting is easier if the wood in medium hardness. Super hard is OK but the cuts have to be fine and thin.
Super soft is easy to move, but the edges of the inlets have a tendency to collapse some.