The Star and Key category System & Examples:
We cannot compare the difference between stars and keys.
Hotels: 1, 2, 3, 4 and 5 star. Apartments: 1, 2, 3, 4 keys
Hotel-Apartments: 1-2-3-4 star.
A luxurious apartment building can be only 2 keys, only because they do not have direct dial telephone in the apartments.
A very standard Apartment building can be 3 keys, only because the measures of the bedrooms are bigger than the minimum required and have direct dial telephone. Therefore it is better to indicate: luxury, first class or standard.
Aparthotel Aguamarina is a 3 star hotel or 1st class apartment.
Apts Bajondillo is a 2 key category or 1st class apartment.
Apts Minerva/Jupiter is a 2 key category or standard apartment.