The strength of composites depends on the direction of the lay-up of the fibres, so it is not necessarily the same in all directions. In fact, the advantage of composites is that you can tailor the material to give greatest strength in the direction of greatest stress

The whole point of development in materials is to get a GREATER strength/weight ratio.

And, finally, it depends on what you mean by "same in all directions". I doubt you could design a structure that gave the same bending flexing tension or compression responses in all axes. (Actually, what about a solid sphere?)