Definitely Sound! I have Phoenix in 10 of my locos and one with LGB, and will be changing it to Phoenix.
I’m with Geoff George. I’ve got both, I leave the sound turned off, and I wouldn’t pay you a nickel for it.
I can’t justify the cost of sound. It is nice once in a while, but it drives you nuts after a while.
You’ve heard of the saying “Silence is golden” Well I beleive that.
Besides it gives the kids something to do.
Aside form the costs issue I mentioned some folks have already mentioned one of the biggest problems I have with sound, its most effective when its reasonably audible becoming apparent as the train comes into view gets loudests right as the train goes by then disipates as the train goes out of view. The problem is that most users soemhow seam to think that there neighbors across town would like to hear the sticattoed static of their pricey sound systen and have set at a volumn that would rival a WHO concert. Some of these guys need to get their hearing checked or maybe inquire if they might need to consider a hearing aid. At a recent show one of the displayers told about another group who had a member in the past that would pitch the sound controls on their engine and on an animated display module so loudly that you could hear it aon the other side of the hall. At the end of the day when it was switched off, an audible releif of Ahhh! was heard from the other vendors.
(http://images.icanhascheezburger.com/completestore/2009/4/29/128854838489347047.jpg)
Victor Smith said:
Aside form the costs issue I mentioned some folks have already mentioned one of the biggest problems I have with sound, its most effective when its reasonably audible becoming apparent as the train comes into view gets loudests right as the train goes by then disipates as the train goes out of view. The problem is that most users soemhow seam to think that there neighbors across town would like to hear the sticattoed static of their pricey sound systen and have set at a volumn that would rival a WHO concert. Some of these guys need to get their hearing checked or maybe inquire if they might need to consider a hearing aid. At a recent show one of the displayers told about another group who had a member in the past that would pitch the sound controls on their engine and on an animated display module so loudly that you could hear it aon the other side of the hall. At the end of the day when it was switched off, an audible releif of Ahhh! was heard from the other vendors.(http://images.icanhascheezburger.com/completestore/2009/4/29/128854838489347047.jpg)
Speak up, Vic. That damn train is too loud! 
About that clown who set the volume that high… hmmmm and where the hell was show management? Or is this part of being free to do whatever one pleases?
BTW I also know at least one vendor - actually the factory rep - who amplifies his &^%$ sound modules/sound decoders through a stereo system complete with a home theater set-up under his display tables. The wise vendors make sure they are nowhere near this sh… head!
Gotta guy like this in our club, and he just doesn’t get the message. H E L P !!!
Crankum up if you gottum… 
(http://freightsheds.largescalecentral.com/users/nicholas_savatgy/_forumfiles/EmoticonPartyDance.gif)
Just for grins, out near the road sign that says, “End of the world, 2 Miles,” I cranked up to full blast one of Phoenix’s best through one of Lewis’ supplied speakers. The speaker was fried in about 30 seconds.
Snicker.
John Le Forestier said:John,
Gotta guy like this in our club, and he just doesn't get the message. H E L P !!!!!
I hope he isn’t the one who knows how to set all the CVs on the fly, in which case you get the guy who does to “reset a few” of his sound CVs. Or even better yet, have the dispatcher route him to a track that has no power.
BTW in my former life in Ontario there were times when I dearly wished I had incorporated trap doors in the floor - train room above the garage - to have certain operators disappear. 
Yes to sound systems on our layout.
We use Phoenix. Great that you can customize it with a computer. And even better that you can trigger certain sounds with our Airwire throttles.
If you’d like to hear some sound on our layout, take a look at this video: