pointer vs non-pointer members of a class

My questions is, suppose we have two classes A and B. I want to have an object of B in class A.

Should I use,

class A
{
public:
    A();
    ~A();
    B* b;
};

or

class A
{
public:
    A();
    ~A();
    B b;
};

As far as I know, in the first scenario, I can initialize the object *b using new operator and for the second scenario, I can initialize b using an initialization list if I don't want to use the default constructor of class B. Which is more convenient to use?