We are planning on going to Belgium and Luxembourg flying into Brussels Aug 16 returnig Aug 23
we are open to ideas of must sees and must avoids.
The only thing I want to note is that all public transportation in Luxembourg--bus, train, etc--is free.
above, train in 2nd class........
That will depend on your interests. For me the must-see were the WW1 sites in Belguim. The VR experience for the Adoration of the Mystic Lamb in Ghent was also very cool. It was also helpful because I'm not an appreciator of art and it gave me the details and history I wouldn't have picked up on my own.