We booked the Magnolia Suite for a July wedding party and worked with the Steamboat company's staff on the menu, so our experience may not be exactly the same as someone who is cruising independently. Although we had some concerns based on internet reviews, we also noted that the culinary management team was replaced in 2010. Turned out, the buffet supper was excellent. Our guests, who had a fairly large number of different dietary restrictions among them, were all very pleased. I'd rate the food as among the best buffets we have had around the country, although not up to the level of a fine New Orleans restaurant where your meal is cooked individually and served immediately.
The rest of the package was just wonderful, as almost all the reviewers seem to agree. The Dukes of Dixieland who played on the top level of the boat, where many of our guests migrated after dinner, were a treat. Summer weather was hot, but the breeze on deck was delightful. The timing of the cruise on a July evening works out well -- we had sunshine, then sunset, and finally twilight. The lights along the river and on the bridges came on as we steamed back upstream.
Unlike most other Mississippi cruise ships, the Steamboat Natchez is the real thing. All the power is provided by steam engines. You can visit the engine room (although it is very hot in July). The only "fake" element is a very minor one, a tiny, invisible bow thruster that they use to get away from the dock.
And just a note for those planning wedding parties and the like. My wife and I feel like our guests really had a special evening they will long remember. The cost -- Magnolia Suite, meal, bar, service, cruise, and the boat's Dixieland band -- was right in line with other venues we looked at that basically just offer a room and food. The event staff are flexible and easy to work with.