You cruise first to the Studios area, then back and tie-off under the bridge in Epcot that goes between UK and France.
You can see the show "almost" as well as being ON TOP of the bridge.
But its nice to SIT and watch the show (light refreshments are now "included" with the cruise).
Its not a "luxurious" thing to do, but it is so difficult to book, it makes it "special".
We really had a fun "Captain" who joked with us about our trip and his "driving".
As far as seeing IllumiNations, (as I said earlier) you are not going to see it any BETTER than if you just find a great viewing spot IN EPCOT around the WS lagoon.
BTW, right AFTER the show, the boats usually venture into the actual WS lagoon for a minute or two (about 100' or so into the lagoon), then return you to the loading dock where you first boarded.
(The whole round-trip, including viewing IllumiNations, lasts nearly exactly ONE HOUR.)
If you can spare the funds required, and get lucky with your booking, its a nice "extra" that most guests never get to do (or even KNOW ABOUT).