Me and my wife stayed in Casino Hotel Carnevale for two nights (17-19 August 2011) and were very much pleased with the hotel's services and the room. It's worth every star of the four indeed.
The room is just great - large, clean, with nice old-styled furniture, big bathroom, nice TV flat panel, Ethernet in the room, non-obtrusive user-controlled air-conditioning, good bed and linens.
The hotel features casino and wellnes but we had no opportunity to try it as we used the hotel mostly as a base for our travelling to surrounding areas (we travelled by car). BTW, the hotel has large free parking just in front of the hotel.
The hotel is positioned quite well - just about 10km from Triest with its shopping and tourist attractions as well as not far (about 20km) from Slovenian Portoroz and Piran.
The staff is very much professional and helpful. We had no problem with getting whatever we needed at all.
The breakfast was somewhat simple but quite enough and of good quality/service.
We would gladly stay in this hotel again.