Garmin sell many devices, so it makes sense that there would be a demand for a unified application to manage all the Garmin devices you own. The app is made by Garmin, so compatibility is a given, and it is free. This makes sense, since it only works with Garmin devices.
Being an app made by Garmin for managing Garmin devices, there are no real alternatives, but you might compare this to something like Blackberry Desktop Software, which allows users to manage their Blackberry devices, or Huawei HiSuite, which does the same for Huawei phones.
Simple to use but basic
Primarily designed for making it easier to keep your Garmin devices up to date, Garmin Express is very simple to use, and sports a particularly clean interface because of that. You can update software, maps, and other location-based information like golf courses through the software. It also allows you to manage other content—both paid and free—that you can use on your devices.
Use the app to sync activities and information to your Garmin account. This can include wellness data from a fitness device, or route information from a satellite navigation system. You can also redeem vouchers and product keys through Garmin Express. All of this is bundled into a simple and clean package.
Necessary for Garmin users, useless for everyone else
The nature of Garmin Express means it is highly recommended for owners of Garmin devices, especially those who want to keep data synced to a Garmin account. Unfortunately, there is nothing of value for people who do not own any Garmin devices, as all of the functionality is built for that purpose.
Another drawback about Garmin Express is the size. Despite being a relatively simple application, Garmin Express requires at least 13 gigabytes of free hard drive space to install, which may seem a little excessive for some when you consider what the app provides. Still, if you use Garmin devices, it is best to keep them up to date, and Garmin Express is the easiest way to do that.