What is advantage and disadvantage of a synchronous counter over an asynchronous counter?
With a synchronous counter (or any synchronous system for that matter), the inputs have time to stabilize before they affect the outputs. This precludes race-around situations, transient output states (think ripple-carry counter), and errant output states. The disadvantage is that a clock circuit has to be included in order to gate the logic (advance the logic to the next state).