The Basic version allows you to select from an assortment of pre-made practice routines. You can preview / change a soundset and play the routine and you can create your own single step routines.
The Pro version provides a wider assortment of pre-made routines. Allows you to fully edit/customize multi-step routines. You also get a Watch Companion App that automatically syncs with the iPhone to access new / updated routines and then sends practice log data (including heart rate) back to the iPhone for tracking and review of progress.