If you only have a small layout, you may be fine with the free app and the DCS Explorer. They come with the new starter sets and I run three MTH locos at a time. It's certainly limited feature wise, but it does about the same things that the Bluetooth Lionchief app does. For small RRs, it's a fantastic option.
If you are thinking of buying another MTH Railking starter set, the Explorer is shipping with them, like the Amtrak set that's available now.
So, for the price of the full DCS system, which you may not need, you'd get another full train, track, plus the DCS Explorer.
It's worth considering, depending how detailed you are going to run.
