'O' was my second Cirque du Soleil performance, but there is no way to compare it to the Beatles show. They are very different from each other, although both worth seeing.
What was the major advantage of this show is a water setting. It is truly beautiful and enables performers to do acrobatics that are not possible in other shows such as synchronized swimming and water jumping. It is rumored that some of the cast are former Olympic athletes. However, it must be noted that 'O' doesn't have any conventional plot. It takes place in a kind of magical realm and it's sometimes very hard to see any connection between two particular scenes. Sadly, this made me less attentive to the show as a whole. The costumes were pieces of art by themselves, truly extraordinary! And the acrobatics were amazing and breathtaking, especially Russian swing, Washington trapeze and high dives. Wow! What this people can do... it's nearly hard to belive and sometimes scary to watch!
What I didn't like was abovementioned lack of plot which made the show kind of boring after a while. Without a story that adds a new dimension to the act it gets less and less interesting with every minute. Also the comedians acts were mediocre - sometimes funny, sometimes nearly cringeworthy. All in all, it was still a beautiful thing to watch. I would gladly watch all the Cirque du Soleil performances in Vegas if I could :).