I had an additional rubber protective sole applied over the existing rubber to beef it up a bit... but I still wasn't happy. Then I went looking for and managed to source a range of different sole options including a cats paw-like "Dr. Sole Original" composite rubber sole, but they were super heavy. In the end I decided I have so many heavy duty boots, and with summer coming, I'd go for a lighter option... so the Vibram.
I'm pretty happy with how these turned out... kind of the way that should be, I think. ;)