Did one Christmas Eve last year and really enjoyed it. Like you stated, they start over by the Yacht Club marina and take somewhere around 10-12 people at a time. They take you around the Boardwalk/Beach Club resort area then about 10 minutes before Illuminations starts, they "Park" the boat under the bridge at the back of the World Showcase. From this vantage point you can see illuminations and all the accompanying fireworks very well. Of course all this is done with the usual Disney banter, cute jokes and general information about the resorts and Illuminations. We ended up being on the cruise with a cast member that worked on the fireworks at MK, so we had tons of interesting stuff thrown our way! Well worth the money in my opinion.