What is the difference between aTV Flash(black) en XBMC?

I only want to use Apple TV 2 as mediaplayer so that I can play movies, music and pictures from network hard disk. Is there any difference between aTV Flash and XBMC?

In a nutshell…

XBMC lets you stream other formats, but forces you to leave the native (simple) AppleTV interface.

The goal of aTV Flash (black)'s Media Player is to provide support for additional video formats through the native AppleTV interface. This allows you to stream media files directly from a NAS drive or networked computer without having to convert them to a special format, launch a separate application or run special server software on a computer.

So if I understand it correctly for both aTV Flash and XBMC Apple TV 2 needs to be jailbroken?

Are there any features what are only aTV Flash and don’t exist in another software like XBMC?

Or is aTV Flash only collection of other software and makes it easy to installe other software like nitoTV, XBMC and others?

 

I have Apple TV 2 with 4.3 software version. If I jailbreak it and install aTV Flash can I normally update my Apple TV to version iOS 5…?

Yes, the AppleTV will need to be jailbroken to install either aTV Flash (black) or XBMC.

While XBMC, Plex and nitoTV are available options to install using aTV Flash (black) the core offering of aTV Flash (black) is the FireCore plugins which are only available to aTV Flash (black) users. 

This screenshot shows the Manage Extras menu aTV Flash (black) provides. The FireCore plugins are listed in the Featured section, whereas NitoTV, Plex, and XBMC are listed in the 3rd party section.