Even though Boulez is renowned for bringing discipline to his orchestras, I still never cease to marvel at how he pulled off these simply seamless, splendid performances. Discipline is of the utmost importance with Debussy: a brass sections that doesn't have its dynamics perfectly under control can destroy "La Mer" in any number of places. The same can be said of the female chorus in "Nocturnes: Sirenes." We have all heard the wobbly, out-of-control chorus in Sirenes, that demolishes all of the splendid orhcestral work that preceded it.
On the other hand, discipline can go overboard and turn into a rigid mechanical performance, and nobody needs to hear an orchestra going through the motions, hitting every note perfectly, but rendering a performance bereft of any passion whatsoever. The trick is to walk the line perfectly between being disciplined and being mechanical, and Boulez has indeed pulled this off.
It is just wonderful to hear a smoothly modulated brass section playing its part with the right level of nuance, and a woodwind section dealing with Debussy's challenging rhythms with ease and comfort. The string section also play their parts perfectly.
I also must tip my hat to Franklin Cohen for his performance in as fine a Rhapsodie as I have ever heard.
Overall, this is an endlessly pleasing Debussy disc. The casual listener can simply enjoy Debussy's music on its own merits, while the more serious listener can enjoy diving into the intricacies of Debussy's score, appreciating the splendid job that Boulez & the Cleveland Orchestra has done.