It’s fine. Could be better.
It has plenty of options for chainring and cog combinations. It provides amble ways of reading the ratios. What it doesn’t do is allow you to save your chainring-cluster combination for later reference. Each time you open the app you must renter your numbers. If your set up isn’t one of those in the standard list included in the app, then you must type in each chainring and cog separately. Being able to save bike set ups for later reference would make this a much better reference, especially since it already allows you to compare multiple bikes at once, provided you enter complete information for each.