You won't see a lot of acrobatics, and there is a short narration in English at the beginning, so it's not the best for guests with limited English comprehension.  Of the three shows we saw in Vegas -- O, Ka, and Mystere, I would rank O first, Mystere second (there's no longer a man in a diaper), and Ka third.  Helpful tip:  if you have time before your trip, join the Cirque Club online for special promotions and check Travelzoo before you buy tickets.  If you can't find any good deals, buy same-day tickets at Tix 4 Tonight (search Yelp for tips on T4T).