Definitely as advertised. It's a converted Windmill with a unique interior and all facilities you could need. The main shower is a bit small, so not that comfortable for tall people (6' and up). We stayed in December, and while the weather was a bit chilly by Malta standards, we were never cold as there is a gas heater in the main room and an electric fan heater in the bedroom.
Location wise, you're in a built-up residential part of Rabat, which has sprung up around the Windmill over the years. You get some alright views from the top bedroom, and every morning we were there, a neighbour was racing his pigeons from the rooftop! It's a 10 minute walk to Mdina (beautiful), with convenience shops and bakeries not far away.
The parking is quite tight, so be wary of hiring large cars, as you'll have to use the street parking - which is easy to find in December, just no guarantee of a nearby spot.
Rabat made a great centre for exploring the island.