Let's start with the good: it's a hotel with good connections to the city center. It looks clean and staff seem nice. The window opens! But if that's all that can be said from a 4* boutique hotel, it's a poor show.
Why? Let's start with the bed. I booked a room with a king size bed and although the photos on the website show a nice big duvet, I had to make do with a single duvet. No, no second single duvet in the cupboard. What the photos on the website does not show is that the bottom sheet goes directly on the mattress. Hygienic? I think not. Then the bathroom. Yes, that towel was completely frayed which at the very latest housekeeping should have checked and taken out of rotation. And perhaps they did that a couple of times, because the towels don't match anymore. While you may not consider either an issue at home, in a hotel (especially a 4* one), you expect different. The whole room looked heavily used. Switches were completely worn off, the bathroom had seen several remodels with the shadow of the previous shaving mirror still clearly visible in the poorly executed paintwork. The shower will soon need attention: the shower screen looks as though it will say its goodbyes to the wall soon.
The hotel as a whole gives a frayed impression (not just the towels). If 'boutique' implies 'frayed' that reference is spot on, but I can do without. I'm sure at some point they were 4* but that rating is lightyears away now.