Edit: Be careful which sound you choose for the metronome, as they sometimes stutter and change the downbeat. In my initial review I forgot that I had changed the sound to Klopfgeist. There are some other sounds that act funny at higher tempos and different subdivisions, but some of them work fine. And the fact that you can change sounds, subdivisions, and time signatures is great.
(Pre-edited review): I’ll preface by saying the interface is easy to use and I like that it is one of the few free metronome apps that allows you to customize time signature, subdivisions, and click sounds. I am a drummer, and having a tool to help lock in more difficult patterns, grooves, and rudiments is wonderful. However, whenever the audible beats are at highish tempos/actual playing speeds (noticed it starting with quarter notes above 120bpm, eighth notes at 64bpm, triplets at 84bpm), there are clicks that sound like digital clipping distortion, sometimes blended with the chosen click sound, sometimes swinging on offbeats. Occasionally, the metronome will stutter off-tempo and change the downbeat, halting practice, defeating the purpose of using a metronome. I only use the standalone app as a practice tool. Be wary if you are thinking about using it in a gigging scenario or spending money on it or its affiliated products.