Overall it’s fine, but it could be better. I specifically asked whether it was compatible with the Simagic DS-8X, and they said it was.
The shifter is compatible, but it requires an additional adapter (which they included). The problem is that with the adapter installed, the shifter sits very high - whereas most people want it as low as possible.
I used the rubber piece they provided and inserted it directly into the shifter instead of using the adapter.
Of course, the rubber didn’t last long, but at least the shifter is now firmly mounted and no longer sits too high.
I’ll probably have to wrap some cloth or something similar in place of the rubber later on.