There is currently in Russia two different statuses for residential estate. The traditionnal so-called “Kvartira/Квартира” and the recent “Apartament/Апартамент”.
Basically, the second status is preferred by developpers as cheaper to build (less admnistrative constraints, insulation/enlightment requirements, no need to renovate/build infrastructure in the surroundings etc…). For these reasons, an “Apartament” is often cheaper to buy, but has its own constraints (no possibility to have permanent registration, 0,5%-2% property tax instead of 0,1% for a “Kvartira”, etc). You need to assess what is important for you in order to make the right choice.