for any given location, penthouse units are always more expensive, especially when the apartments include a terrace - smaller apartments are also more expensive per square meter than large apartments.

other factors that determine the value of an apartment is the availability of  parking space in the building, multiple elevators, the age of the building, and facilities such as swimming pools and common party areas available to the residents of the building.  

other considerations that affect prices are the distance from subway station, supermarkets, shopping malls, and parks or green areas.