I love the synthesis, you can make a wide range of really interesting percussive (and tonal!) sounds with it.
It takes a bit of an effort to learn, but it's a fun process (at least it was for me). I'm very happy I went with the Volca Drum, instead of using a drum machine with limited, pre-defined sounds.
The unit is small, so I fear for it being fragile, but build quality seems quite good, so I hope it will last.