I don't think these products are directly comparable. I think Final Cut Pro probably maps better to Adobe Premiere Pro... But even then, it's not a complete overlap. There are things you can easily do in Premiere that you can't easily do in FCP, and vice-versa. In general, I find that Premiere is a bit more powerful/flexible than FCP, but FCP is much better software and does what it does much smoother and much faster.

No, they're for completely different use cases. While it's technically possible to edit a video in After Effects, its main use case is compositing VFX and advanced motion graphics.