As far as the less wire goes, there really isn't any added wire when using flex strips and SSC's. The SSC gets its power and signal on the same cable and you could put the SSC on the top of the snowfall tube and hardwire the strip to the controller but even if you still use the 3 pin connector, there will still only be one wire going to the top of the tube, just like the FAST tube. It will just be a different type.
If you are creating a static display, then I would go with the FAST tube because like you said, they are set it and forget it devices. If you intend to create an active display, then you will need a method to control them, even if it is just turning them on and off. You would need an AC controller to do that and even then, there is the issue that many of these devices don't work well when connected to the output of a dimming controller. When you add in the cost of the AC controller and possible relays to switch them on and off during your sequences, the cost savings just disappear.
As you also said, with the SSC setup, you not only have full control over the rates and timing, you have dynamic control over the device. This allows you to change the rate, timing, color, and even pattern to suite your sequence as it runs which is something you simply cannot do with FAST tubes. Sure, there is more work to do this but with the advances in NutCracker and Vixen, even that is not all that hard to do anymore.
