I just had a not so pleasant experience with my Dynabar at Brighton beach today. The rope snapped, causing the pulley to slingshot into my thumb, then snapping the safety rope from the harness. My kite went sailing away, luckily landing on the beach for someone to grab. I was left in the drink practising my swimming strokes.
The dynabar was a Dynabar V7 XT bought march 2014. I kite maybe 2 times per month on average, so we are looking at 35 times - say 70 hours. I weigh about 80kg. There is no evidence of wear on the rope. It snapped right at the stainless anchorage, any damage here is near impossible to sight - you would need to disassemble.
Overall my experience with the Dynabar has been good. After this I would not recommend that anyone use the product with the rope. If I can get a new pulley and hook I will only be using the stainless runner. Failure of the rope is very dangerous, and could of been worse if the wind was stronger or a trick was attempted.