C: Assigning structures

suppose we have the following type:

typedef struct {
    int bar;
    int baz;
    int foo;
} Something;

In order to do a copy, I usually do something like:

Something a, b;
...
memcpy ((void *) &a, (const void *) &b, sizeof(Something));
But also the following is legal (and far more quick to write).

Something a, b;
...
a = b;
Is there any disadvantage in doing the second one?

/* A subroutine of gimplify_modify_expr.  Replace a MODIFY_EXPR with
   a call to __builtin_memcpy.  */

I think that's it.