The room we were given for the first night was very noisy and we couldn't sleep at all -- the windows were very thin and faced the front road. We complained and the night after they gave us a better room on the rear side.
Apart from this, rooms are ok but with with some unpleasant quirk: for instance, in our room there was no light at all on the bedside table, just a small LED that was useless (we like to read before sleep). The whole place was un-cozy.
The parking lot has a very small entrance: you will be able to park there only if you have a compact car! Also, it is unguarded and there is no access control -- anybody could enter.

We stayed at the hotel August 2007. The hotel was very nice and the staff very friendly.

Summary:

Location:
Castelsardo is 73 km. from Alghero's Airport and public transport is not good. We flew with Ryanair and at that time at night we could only get there by Taxi which is € 90.- The town is very nice, very picturesque.
The Hotel: Over the main street, in front of the beach. Near shops and restaurants. As it is really new, it was half empty and thefore very quiet.

Staff: Even though their English was not that good, they made every single effort to understand us and satisfy our needs. Excellent people, really friendly.

Cleanness: Very Good.

Breakfast: Even though you need to go to the "Riviera Hotel" to have it, it was simple but with a high standard. The service, excellent.

Price: Great value!

Conclusion: As the previous review, we did not originally booked this hotel. We ended up here after having had a bad experience in a nerby accomodation. We had a great time and felt that this place and its people fully compensated our previous bad experience. We really recomend it!!

We originally booked the Pedraladda Club Hotel but on arrival were told that because of a burst pipe we would either have to take a lower standard room (awful pokey thing above the pool) or go to another hotel. Anyway, cutting a long story short we ended up at the newly refurbished Riviera hotel situated in the old Hotel Janus building.

After booking in at the Riviera Hotel proper we headed a few short minutes up the street to the building housing our room. We had a room on the 3rd floor which was as luxurious as any Marriott room you'd find in the UK. Large, roomy, clean and with a modern design and huge bathroom this was a welcome relief after the stresses caused by the Pedraladda.

The balcony looked out onto the bay and was accessed via double glazed french doors but the room had good aircon if it got too hot.
Even though we hadn't booked it directly, we couldn't have been happier as it looked like we had the building pretty much to ourselves. Breakfast was taken at the main Riviera hotel down the street which was a simple affair of just coffee, juice and a couple of croissants.

In the evening the hotel restaurant Fofo takes over this room and we had a lovely meal here out on the terrace overlooking the bay as the sun set over the headland. Not cheap but very nice nonetheless.

Whilst we didn't see any of the bedrooms at the main Riviera the facilities and public areas were of a high standard.