They are absolutely worth it. Like @ia_camper mentioned above, On The Go is a very popular and reputable brand. You’ll want to research the size of the tank and capacity to find one that will work best for you, and decide where to put it (whether to mount it or just set it somewhere when you use it).
Be sure you understand how it works and the maintenance involved. For example, when I need to regen mine I remove it from the RV, drain it, pour regular table salt in it, run water through it, and reinstall it. Thats why many people prefer not to mount it and just set it up outside or next to the sink inside.
Here’s a quick video of the regen process with the On The Go.
Thats pretty much it.