Expensive, little filling, not very good

The pins themselves and the refills are very expensive in the price / performance ratio. For this price you would expect more capacity and better quality. With me already a "dud" was often here where just the mine was broken.

Positive:

+ Rich colors
+ Colors dry quickly and do not blur
+/- Pin material is not cheap but also not high quality
+ Easy swap of mines
+ Wide range of colors

Negatives:

- The "indestructible" eraser dissolves and also relatively quickly
- Eraser can not be exchanged
- Priced very expensive (pen and refill)
- The signature disappears in long and direct sunlight, with heat by hairdryer or lighter
- Some mines that simply no longer write at half the capacity will

I'm not completely convinced