Definitely location is the strongest of this apartment. Just walking distance from every interesting places such as plaza del sol, plaza mayor, San Miguel market, la cebada market, El Rastro, calle de Argumosa (full of bars). La Latina metro station is 2 blocks away.
The weakest part is the bed of the main bedroom. If you are staying 5 nights or more, like us with Children, you will find that bed uncomfortable after a whole day out walking. I would suggest Marta to change this bed for a better quality one, mattress needs to be improved. You literally sink and your back would never stay straight to rest.
As far as 2nd bedroom is concerned, the upper bed needs protection against possible kids falling, as it only has a ladder to go up but it just doesn't turn into a protection for those kids that are not used to bunk beds and may roll at night.
Toaster burns bread. Corkscrew broken, no wine glasses, Internet access is such a pain as signal keeps going out permanently.
There is only one duvet for each bed, extra blanket would be proper if you are using the sofa bed in the living room or if your kids just feel cold.
The area is full of restaurants that offer delivery or you can just order and take away.