We had a mixed experience at the apartment and it was far from what you would expected, especially considering the price for it (~300 euros per night).
Pros:
Really good location with most of the touristic attractions around one kilometres away.
It is easy to to get inside the apartment, with just a single code for both the main door of the building and the door of the apartment.
The internet worked relatively well.
Cons:
Although you just need the code to get in, the code given to us was wrong, so we actually had to phone them to get the right one. We got lucky one of us had an European phone, otherwise we would have no way to communicate with the company.
The apartment had a washing machine, but it had no tide pods at all, so we had to buy a whole box to use just 2 of them, which doesn't make much sense at all.
The towels also didn't have a clean aspect and even had some stains. The walls were also dirty and stained, which made the experience even worse.
The bathroom's box had no place to put the soap, shampoo and etc, so we had to keep moving it around. And those utilities were also not included in the stay.
The position of the living room doesn't make much sense at all. The sofa is in front of a wall and you have to look to left to watch the TV, so not comfortable at all.
General conclusion:
I wouldn't recommend at all, unless you only care about the location.