In order to really see the Panama Canal, you need to transit the entire system. Since our cruise ship only went as far as Gatun Lake and then returned to Colon to await the return of the passengers who booked excursions.
We signed up for the tour boat excursion that traveled form Gatun Lake all the way through the canal including the Pacific locks and out into the Pacific Ocean. We disembarked the Coral Princess in Gatun lake by launch to shore, where we took a bus to the tour boat dock.
The biggest advantage to taking the tour boat was the change in perspective of what you are seeing. On the cruise ship, you are always at least ten stories of above the water all the way to 15 stories.
Traveling through a water ditch is not always that exciting, but the canal has a lot of vessel traffic and currently there is a lot of maintenance work going on. There is also a lot of work associated with the building of the new larger locks. Traveling at near the water level gives an up close and personal feeling. You can really feel the change in the water level as the vessel descends to the Pacific Ocean level. And of course there is always that bit of excitement as you realize the large ship that is going to share a lock with you would crush our small vessel like a bug if there was any miscalculation as it slows upon entering the lock behind you.
Below are two short videos of the lock thru.