Dave made me aware of this thread. Thanks, Dave! First, I never had the honor of serving in the military, so Bob Delbridge, that's not me.
Yes, Chuck has seen my American Models FA2 running on the Houston S Gaugers club layout. It will pull a 20-car train for the full train show (6-8 hours) before the battery is empty. I am (currently) not interested in sound, so none of my installations include sound. However, as Dave mentioned, S-CAB can support sound.
Basically, the differences between the systems are that S-CAB requires you to purchase a dedicated physical hand-held throttle (my personal preference), whereas the BlueRail Trains system relies on you owning a smartphone or tablet. S-CAB uses radio-frequency for the method of communication, while BlueRail Trains uses Bluetooth technology. Both require some sort of receiver to be installed in the locomotive. Power for the locomotive and onboard electronics can be taken from the rails or from an optional battery onboard. Your choice.
CVP Products makes a physical throttle for the G-scale market but it uses the exact same transmitter/receiver combo that S-CAB uses, so you can purchase the CVP T5000 throttle, if you prefer (they also make receivers that fit in HO-scale or larger engines). The way I see it is that the S-CAB throttle is the "basic" version for day-to-day running, while the CVP one is for the "advanced programming" version. I do plan on purchasing the CVP throttle, but so far I have been perfectly happy with the S-CAB throttle by itself for the past 5+ years.
What sold me on the S-CAB system 5 years ago was the use of the onboard battery, and the convenience of from-the-track charging (no swapping batteries like the G-gaugers have to do, and no ugly dangling exterior plug). Place the engine on a section of track that has 6 volts or more (DC, DCC, AC) on it, and the battery will fully charge in about 8 hours (I let mine sit overnight, because the S-CAB system has overcharge shutdown protection in it).
I have no personal experience with the BlueRail Trains system, but with S-CAB I know that Neil Stanton sells the Soundtraxx Tsunami sound decoders. So, if you have heard one of those sound decoders, you get the same with the S-CAB system. Neil has the older and newer Soundtraxx decoders available, and he also has higher-amp DCC decoders, too (which may be of interest to those of you wanting to use smoke units, I don't know). Basically, the way S-CAB works is, its receiver is hard-wired to a DCC decoder of your choice. For a current list of which ones are available, browse Neil's page at
http://www.s-cab.com/price-list.html
If you have any questions, feel free to contact me. Disclaimer: I am just a happy customer of the S-CAB system; I do not get compensated. 
- Peter.
