Conclusion:
I prefer the VGA adapter.
The HDMI adapter makes problems - now and no video / audio output, and no one knows why - also tested in the AppleStore, with multiple adapters and cables and ipads.
back home - it goes again. Crazy Apple iPad world!
now on the benefits of HDMI video and audio quality is better than VGA and comes with a cable.
the benefits from the VGA adapter:
+ Always works
+ Uses the full height of the screen from (HDMI has black borders on all sides, since up to videos and photos bears no full HD resolution.
both adapters reflect the screen contents 1: 1 with the iPad. 2