Three stars because the Fuji is no better engineered but is much more expensive.
For reasons I won't go into, we own both the real Fuji hood and the one by JJC.
The example from JJC is almost identical.
As stated by another reviewer, the colour being the only difference between the two (this difference in colour being visible only when they are both in hand together and not really noticable when on the camera).
They are both made of aluminium alloy (not plastic) and they both fit the camera perfectly.
On the Fuji example, one of the three mounting 'fins' is in the 'top of lens' position when screwed fully home. The copy matches the Fuji's position exactly.
The X100 camera functions perfectly with both.
At the time of writing, the price for the copy adapter/hood is about one quarter of the Fuji one.
I would buy the copy first. If, for any reason, you are not satisfied with it, I would then buy the Fuji one and use the JJC for the 'rough stuff' where the hood may be knocked and damaged.
The JJC example is not a cheap lens hood, but the Fuji one is far more expensive and functions no better whilst in service on the camera.