For someone doing business in Koln, this hotel couldn't be better. It's a very short walk from the train station and taxis, (and the train station is dead-simple, dead-cheap to access from the airport) so the location is pretty much perfect for pretty much everybody who is doing the plane-train thing and is in town for business.
I can understand it's a little basic for family vacations. No to worry. There are lots of other great Koln hotels that provide that service. It has every comfort and convenience that I want in a business hotel.
I don't need a full-featured business center or meeting space so I didn't assess what they offer. I'm not qualified to comment on fitness facilities, please note. If these are important to you, check other reviews.
The breakfast is pricey but excellent and, as far as I can tell, priced only at the upper end of normal for business hotels. I didn't feel it was overpriced for what I was getting. Having said that, if I had more time to browse around (that is to say, if this wasn't a business trip) I'd look elsewhere for something that costs a little less. But time is money. I had arrived at midnight and was headed out the door for my first meeting of the day by 8:30, and this hotel was a perfect base of operations for me.