I agree with the PPs. We love Cirque shows, and have even planned overnight trips to Washington, DC (a 3 1/2 hour drive for us) when they play there. We really enjoyed La Nouba, and would recommend that every frequent WDW visitor eventually fit it into their scheudle. But you're right, $464 is a pretty steep price for 4 adults. I'd recommend looking at some of the other booking categories, which will give you an equally enjoyable evening at a lower cost.
That said, another option to consider is a day at Sea World, instead. For about $150 less than the amount you quote for La Nouba, you could have 4 adult Sea World tickets. One of the shows at Sea World, A'Lure: the Call of the Ocean, will give you a flavor of the same type of show as La Nouba. It isn't nearly as long as La Nouba, and doesn't have the same unique music as a Cirque production, but it's a fun little show. And hey, for $300 instead of $464, you also get to see Shamu and all his buddies, too.