A rhythm coach is a great tool to improve your timing on the drums. It helps you progress, learn, and become more precise and consistent. Most drum modules have a built-in rhythm coach which is why eXaDrums had to have one! My first introduction to a rhythm coach was the Roland RMP-5, so in it's current state, eXaDrums' rhythm coach looks very similar:

As you can see, it's not finished, but it already has the most important features:

• It's synced to the click: the bottom plain circle moves from right to left just like a metronome.
• It has two virtual LEDs that blink on every click for the green one, and every first click of a bar for the red one (which isn't shown on the previous picture).
• It has a "velocity meter", located on the left side of the window. It gives you the strength of your hits.
• And finally, it has what you could call a "jitter monitor" which shows you if you're going too slow or too fast with regards to the click.

Of course, the user interface will be improved in the future, but I think that it's important to emphasis that pretty much everything exists in the code. The last updates allow to sync the metronome to the GUI, monitor the strength of the hits, and their delay with the clicks. Since it's already possible to modify the click's volume, it will be quite straightforward to add the quiet count training programs that commercial rhythm coaches offer. Basically, it'll be able to do everything a regular rhythm coach does!