We stayed here for 4 nights in September 2011. This is very much the end of their season, so the whole place was pretty quiet, although this suited us.
Baia Sardinia itself is a nicely set-up little resort, with a good selection of hotels, villas, cafes, bars and restaurants, and a few little shops, overlooking the beach. The beach is lovely, the sea clear and turquoise, and there are some activities (pedaloes, speed boats, excursions etc) available for those who feel that way inclined. Having visited a few of the neighbouring towns, we much preferred this one. The hotel is in a nice location, a pleasant 2-minute stroll to the hub of the action.
Mon Repos was clean, spacious, well-run, well-maintained and the staff were all very friendly. There are three types of rooms: standard, comfort, and superior. We'd booked a comfort room but discovered upon arrival that we had been upgraded to superior, which meant we had a large balcony, with sun loungers, overlooking the bay. There was a good selection of food available at breakfast. The restaurant attached to the hotel - Il Corbezzolo - was good and is currently ranked on tripadvisor as 1 of 9 in the town. Hotel guests get a 10% discount.
Another nice touch - they provide towels which can be used for the beach or the pool, and exchanged for clean ones whenever you need them. Helpful to cut down on suitcase weight!
So, on the whole, a great hotel, in a nice place, and the only mildly negative things I could think of to say are, firstly that the bed was so hard it was like sleeping on a concrete floor (it even gave me pins & needles on whichever side I was sleeping!) and secondly the air-con was antiquated and didn't actually change the temperature in the room.
But otherwise, recommended.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC