We stayed in Abbazia Club Hotel for three days in October 2014. The location was nice, only 500 metres to Lake Balaton and maybe a few hundred metres to Keszthely centrum. We stayed in Red Building number I, the room was clean and comfortable. There weren't so many guests so we didn't hear much noises. The staff was very helpful and spoke good English.
The rooms didn't have a WiFi of their own (this was the only thing I didn't like), but the reception had wireless connection which could be used 24/7. Breakfast was a basic one.
All in all, the hotel was a good place to stay.