Comfortably large space, soundproofed walls, and keycard gates to keep random people from walking in.
Apparently this place was a dingy hellhole until its current owners bought it. Over the last few years, they've made massive improvements, including remodeling nearly every unit. It still has its problems, but the process is ongoing. Reinventing a >50-year-old building takes time, after all. Even now, it's one of the nicest apartment complexes my family was able to find.