My first experience was during the day and I was on the side of Bellagio and facing the Eiffel Tower. That was pretty wonderful and I got some great shots. They played a Sinatra song and towards the end I (and everybody standing near me) got a light "Bellagio fountain" shower.... that was unexpected, but... felt kind of good!
The second experience was at night and I was on the other side (next to fountains, but on the Paris side). The show was lovely and Bellagio looked quite lovely all lit up. More great pictures, no shower, but the song they chose was some super-patriotic one that I didn't like that much. Ah well.
The shows are very short, but I think they're definitely worth the ~5 minutes of standing and watching.