Great report so far.
The Hilton looks like many Hiltons and the style is very similar to Vieanna, Düsseldorf, Frankurt and certainly nothing special. Though the location for an overnight is good.
By the way, all rooms have been renovated a couple of years ago and the lounge moved to the ground floor. COmpared with my frequent visits there back in 2007, it is an improvement. Back in 2007 the rooms lokked like this:
http://www.hotels-and-travel.de/hote....htm#s20070924
Looking forward to the next reports (and also following your trips on instagram)