On our second attempt to see the canal, we had already returned our rental car and chose to take a city bus. Unfortunately we got the wrong bus and ended up getting off at a station that was a 20 minute walk/run from the locks. Whoops! It might have been worth a $5 taxi to save us the hassle.
I think the Panama Canal is worth going to, just because it’s the only thing most people know about Panama and besides, it’s only $15 per person. It was kind of cool to see the locks and I enjoyed it even though I am not a huge boat person. But if I were to do it again I would read David McCullough’s Path Between the Seas (I really enjoyed his biography of John Adams), and then plan my transportation to the locks carefully so as to see the big boats without being rushed or bored.