I'll start with the good things:
The apartment is beautifully designed, very tidy... was spotless when we arrived. The location is also incredible - 5 minutes away from '9 streets' but still very quiet. Twan was also always responsive, just like the hundreds of people before me have mentioned. Also, you wouldn't believe the view from the bedroom.
The not-so-good things:
Having to pick up the keys from a location 20 minutes from the apartment. I understand that the property is run by a company (not a private landlord), but I can't figure out how that's better than having someone open the door for you at the apartment... without having to walk 20 minutes back and forth.
Also, the kitchen was also spotless but some important items missing such as a kettle, paper towels, etc. Also a land phone would be a huge upgrade.
Other than that - we'll most probably come back again. Thanks for everything Twan!