I saw this show a few years back and it was my first Cirque du Soleil show. I remember being spellbound with my jaw dropped the entire time. The performers are amazing and the stage is like one big pool. Pay more and sit in the orchestra section - it's a totally different experience than watching it from the nosebleed seats when you can see their costume details and facial expressions.
My friends and I actually got tickets on a whim the afternoon before the show. If you walk up to the box office and it's sold out, ask about cancellations - there's always a few of those each day and you might be able to get seats. Of course, the seats aren't discounted or anything. You just get lucky for procrastinating.