One of the big Enchousen things is that it covers the Kintama and Courtesan of a Nation arcs, which is a turning point on the series, become more plot-oriented and entering the whole political concept of the story, since it's based on the Edo period.
Although you won't laugh as much (which is one of the major strong points in the show), you'll crave for more as you watch this one, proving that Gintama is not just your everyday comedy series, but also one of the greatest shounen anime of all time.
The OST is also a great feature here, which makes battles even more exciting and totally worth the wait.