Never again!
The hotel has indeed clean rooms and complimentary breakfast (Yet the breakfast room is far too small, people had to wait for a table every morning and it has a Mc Donald´s-like atmosphere.) But that´s about it concerning the good points. The hotel staff is extremely unfriendly and not helpful at all. We had a problem with our voucher on arrival, which turned out to be the hotel´s fault, but there was no excuse, on the contrary they charged our credit card for the first night. We had to talk to the front desk people several times before this problem was solved. 
But the worst is the bar on the rooftop. Every night there are people who are not hotel guests queuing up in the hotel lobby waiting to get up to the bar. Apart from the fact hat they block one of the elevators, this gives the hotel a very cheap character and it is miles away from the other Marriot hotels I know. The hotel is good for young people who desire a hostel-like atmosphere (loud music in the lobby), for everybody else I would advise to go to one one of the two adjacent hotels (Four Points Sheraton or Staybridge Suites). They seemed to be decent hotels.