Some good comments here, all valid viewpoints as this is a very subjective question. I agree that you should try running some temporary wire and test the extra channel(s) if you can before making the permanent investment. Best way to know for yourself.

It's true that Dobly EX is a matrixed 6th channel but DTS ES can provide a discrete 6th channel. Available in a few titles (Lord of the Rings 1/2 Extended Editions, Chicken Run, etc). Hopefully more and more to come.

-Dave

M80s VP150 QS8s EP500s
ravenmanor.com/cinema/