"The new Powered Up hub works fine with the free iPhone/Android remote app but that app has it's limitations and bugs, particularly when using it on a train motor. The hub cuts the power off to the motor when you leave the app (like answering the phone or checking emails) or stepping out of range. Also, as of the current phone app version, it loses the motor speed function when the phone screen turns to sleep, which requires you to reconnect your bluetooth connection. So I purchased this remote to get around these frustrations. This way I can leave the train running when I use my phone for other things.
The remote is very small and compact, 2/3 the size of the old Power Function IR remote. It lets you control both A and B ports of the hub with each +/- buttons (the app's train sub app is limited only to port A, although you can alternatively use the Batman sub app to control both ports). The remote can also switch controls for up to 4 hubs by pressing the green button to toggle between hub channels (each hub will be assigned a color and the remote's LED will change color to other paired hub). Another advantage is that you can simultaneously control 2 hubs on a same channel, which is helpful to train builders that use 2 motors/hubs on a single long/heavy train.
On the slight minus side, it needs 1 battery more (x4) than the old Power Function version. Also it's a bit pricey considering that there is a free app available.
My recommendation is to stick with the app if you are ok with it. But if the limitations annoy you, or if you are an advanced builder needing to control 2 motors simultaneously on the same set of buttons, try this remote out."