Cameras in that price range are classified as "budget" cameras.
That means they have a minimum of features.
You are unlikely to find any budget camera that will let you zoom while shooting video.
The ability to do that adds some cost to the camera.

Only the Panasonic FH2 has optical image stabilization.
The other two only have digital image stabilization,

It is really difficult to compare budget cameras because the big name reviewers do not review budget cameras.
Just pick the one that has the features you want/need.

..