If time or destination is not a big deal I've heard it is a good way to travel. There is a limit to the # of passengers they can take due to regulations, 12??. An old Navy friend did it a # of times and liked it. Meals were with the ships officers. There is one catch, some times the ships will change destinations. You get to see places other than tourist destinations. Time in port varies a lot and the area around ports isn't designed for tourism! You need a fairly high tolerance for sleaze! Cargo ships don't have active stabilization so be warned. Think of it as an adventure. I'd do it but wife has heard too many old Navy stories.
Gene T45, I've flown on military transports and on the Ship's COD on & off the carrier. If anyone thinks airliners are like cattle cars you ain't seen nothin' till you've flown Carrier Onboard Delivery. After the passengers are seated they fill the aisle with cargo! But takeoffs & landings on a carrier are a pretty neat experience. Landings are what you might call abrupt.