Stayed at the Repubblica Marinara Hotel for one night in July. Our flight arrived late the night before and reception were friendly and quickly checked us in. The hotel is located about a 30 minute walk from the centre of Pisa but I would recommend that you take the bus which are pretty frequent. There is a bus stop just near the hotel and you can buy tickets from reception for €1 for 60 minutes on bus. Reception were helpful with directions. We took a taxi from airport as it wouldn't be too easy to find at night.
I thought that the room was fine and had everything we needed. My one complaint was that the walls were quick thin so you could hear everything next door! Breakfast was good, typically European with good choice of cereals and pastries.