My stay at the Landmark boutique hotel was a tale of two halves: In the first half, there were a couple issues regarding service and amenities in the room that caused some friction. However, after bringing up concerns with management they were very proactive, took feedback well, and ensure the rest of our stay was pleasant.
Outside of this experience, the amenities and hotel are beautiful. It's elegant, chic, and the rooms are the kind of rooms you want to spend time in even if Medellin's beauty beckons.
The food choices in the hotel (run by third parties) are ok. We preferred Smash since it had better service and healthier food. However, there are plenty of great food choices in a 5-minute radius. Also, it is fairly central to many of Medellin's sights and the area around it is fairly quiet versus other areas in El Poblado.
Highly recommend this for couples or solo travelers looking to stay in a comfortable, stylish place, with a diligent team.