My review concerns the Schneider refill as I haven't used the marker ink yet.
Like other refills from the same manufacturer in the past, they initially require a few days of "breaking in" during which, after one or two continuous lines of writing, they stop writing as if the ink has run out and you have to wait for the ink to flow or shake it like a thermometer to continue.
After this period, it gradually smoothens out and writes decently with a somewhat light and soft color depending on the pressure. With a little pressure, it is soft but somewhat faint.
The size suggests that it will probably last quite a while, but I can't say that for sure yet.