I got the closeout price of $500 for the HK AVR520 at J&R which is now enroute. I'm using it for 50/50 HT music but bought it before knowing anything about HT. Now I have learned that the majority of action movies are using DD EX which the 520 won't decode. How big of a diff is there between DD and DD EX. Is it worth the extra money for the 525?