Life can be unfair, and I think Liege (or Lüttich or Luik depending on who you ask) is a good example of that. The city is rather nice. Its not as pretty as Ghent, and its certainly way nicer than Cologne. I would put it on par with Antwerp and Brussels. So why then does nobody go there?
Overall though, I can highly recommend the hike to anyone who might be interested. The Ehrenburg castle is fairly unique in Germany. The ruin is fairly well preserved, the French having opted to burn rather than detonate the castle.