Can't rate this inn highly enough. Went for a girls holiday towards the end of the season, in September.
It is situated in a tiny, very quiet street only minutes walk away from the bars and restaurants. The house is a spectacle in itself, lovingly restored and furnished with beautiful antiques. The rooms are enormous, the beds comfortable. Air conditioning all remote controlled. The family suite is like a large apartment.
But what differentiates Casa Alberti from most inns/bandbs/ from most is that you are genuinely welcome to come and go as you please (given keys on arrival) and use all the facilities, including the kitchen, terrace, library etc and treat it as your home.
Breakfast is pretty much whenever you want it (unlike most guest houses where it is over long before most people get up) and is a feast of fruits, fresh patisseries, breads, cereals, locally made jams etc and endless supplies of coffee. There is, during high season, a japanese cook in the evenings (though not while we were there).
One night, after a long tiring day at one of the beaches, we opted for a stay at home evening, instead of wandering out to one of the many restaurants within easy walking distance, and had the most delicious meal, sitting outside on the terrace, with all sorts of delicacies we had bought at the local supermarket. Popped on one of their cds and made ourselves right at home. It was perfect.
The couple who run Casa Alberti were absolutely charming and couldn't have been more helpful, giving us endless advice on where we could eat, which beaches were best, making bookings for us at the local tennis court. Nothing was too much trouble.. We felt welcomed as if we were family.
We hired a car from the airport (all of 10 minutes drive away), used Casa Alberti as our quiet refuge, and went off every day for an expedition in the car to different beaches. We did venture all the way across the island to Ciutadella, but Old Mao had far more charm. And Casa Alberti is the jewel of Old Mao.