What are the differences between Normal edition and the GotY (Game of the Year) edition

There is still no definitive list, but there's a pretty comprehensive review here.

According to this guy,

• PC has better textures and allows to zoom in closer,
• PC loads faster,
• when playing with a mouse you have minor conveniences like hovering on top of aliens-in-view icons to see hit percentages (I'm playing with a mouse and I've never knew it).
• Important: multiplayer is not cross-platform, so you better follow your friends.

Reviewer explicitly states that he felt no tactical performance gain on any platform.

Tactical view grid should also be classified as a minor convenience - after some hours, you'll be easily telling distances at a glance.

I have basically answered my own questions by playing it. The versions are all practically identical, besides graphics.

The only difference, is release on systems besides PC is delayed more than PC. SO once the PC version releases, it takes awhile for the other versions to get released.