Is EX worth it?

I'd like to hear from people who have EX processors and use a rear effect channel? I am in process of building a theater and am unsure if I should go this direction or wait. I hate the thought of buying a pre/pro only to replace it in 6 mo. Let me know your thoughts. Thanks.
I just read an interesting article on this topic. Check out the September/October 2000 issue of "The Perfect Vision" They have an interesting comparison of Lexicon's Logic 7 and THX EX. It brings up some good points both pro and con regarding the "envelopement of sound." Hope you find your nirvana.
I dont have a official ex system but i recently connected a pretty good pro-logic preamp processor to the suround outputs of my dolby digital/ DTS processor in a ex fashion, and while its not a huge advancement over strait 5.1 it has some awsome effects, and Unless your looking to spend only around 500 dollars on a processor getting a new processor or reciever with ex capability will not set you back any more money. If you dont like the ex effect you can just turn it of and use conventional 5.1
Welcome to the WONDERFULL(SARCASTICALLY) digital age!Where computers are outdated in 3 months and now even home theatre processors in 6 months-or so it now seems.What's next,home control or appliances?Anyways,my opinion is, unless you can afford the likes of a Lexicon or equivelent w/upgradability,who cares.If you don't mind the additional components on your rack,the advice from Beoskerp above will work just as well,or even modules from a music store(electronic instruments) such as digital delay,simulated stereo(from mono for pro-logic rear),frequency crossovers,even the good ol quad stereo surround(from "stereo" for DD and DTS rear).Toys,toys,and more toys.The advice from Listen above is a DEFINITE starting point.