We stayed for 2 weeks in February, to relax after a 10-day trip through Rajasthan. As other reviewers have said, the apartment itself is (practically) faultless. Lots of space, inside and out, down a quiet back-street, comfortable and stylish, with great mod-cons such as satellite TV and Wifi. The Wifi isn't that strong (not enough for good Skype connection when I tried) but that just encourages you to stay a bit more out of contact, which of course is the point of a proper holiday. The only other fault is the kitchen utensils are sparse if you do want to cook - but the housekeepers Sekhar and Bim (who are fantastic) will find what you need.
You do have to know what kind of Goa experience you're after when choosing Casa Mia as it is in Calangute (albeit a quiet part) - the most developed (overdeveloped?!) part of Goa. However if you don't mind or want to ignore the hustle and bustle of the nearest beaches, it's easy enough to get to the less developed places to the North and South, either with one of their excellent drivers (Neal) or by hiring scootersMore