Introduction to OOP

Chapter 14: Polymorphism and Software Reuse:

Advantages and Disadvantages of Each Mechanism

Composition is simpler, and clearly indicates what operations are provided.
Inheritance makes for shorter code, possibly increased functionality, but makes it more difficult to understand what behavior is being provided.
Inheritance may open to the door for unintended usage, by means of unintended inheritance of behavior.
Easier to change underlying details using composition (i.e., change the data representation).
Inheritance may permit polymorphism
Understandability is a toss-up, each has different complexity issues (size versus inheritance tree depth)
Very small execution time advantage for inheritance