I've had one for about four years. Fitting was fairly straightforward. The instructructions are excellent and easy to follow.

I needed to make a spacer (about 6mm thick from memory) to achieve the correct gear spacing. Its performance has been faultless with improved starting and running.

The only downside is that it doesn't look original. It's similar to the Bosch magdyno but slightly bigger.

Konstantinos Manolopoulos wrote:

My 1931 Scout came with one which worked very well as a magneto but at some point the previous owner had made a short cirquit and charging was not working. Frantisek Daniel at Vape helped with shipping back and forth and repaired the little regulator  free of charge as it was pbviously out of warranty. 
construction is perfect and starting and running faultless too.