It was a very pleasant stay at Østerport for business and then vacation.
The biggest highlight was its location to the Metro and S-trains! You literally just needed to cross the street to reach the train station! Also, if you like to walk, the hotel is within walking distance to many popular attractions in Copenhagen.
The room was big, nice, and clean. Nothing extraordinary, but Scandinavian standard, so happy with that.
I will admit that I was a bit reluctant to come here after many people's reviews about the noise from the train. The rail is indeed right outside your window, but you quickly get used to it, especially if you have lived in bigger cities before. In my opinion, it is no worse than living beside a busier road. I didn't even need to use the earplugs the hotel provided.
The downside of my stay, however, was the luggage storage. It was free, which was great, but it did not feel secure. You place your bag in a room with no lock, supervision, or number tags/name tags. Anyone, even people who are not guests, could walk into that room and take a bag as there was no supervision or security! I worried that someone would take my bag by mistake or just rob it.
Please, Østerport, the least you could do is lock the luggage storage room, keep a tag system, and have the reception leave and retrieve the bags using a number system.