One also to consider if you fancy an evening in Pollensa Old Town (please do this - It is a totally different experience to the Port) is El Brio.
Although off the main square, in a little square of its own, they do a great set-menu, at a very good price. Not big portions, but what it is, is very nicely done.
Leave the top of the market square, heading through the alley to the right of the church. Follow it to the right and right again and eventually it brings you to a little square with the old fountain with a cockerel, called Placa Almoina.
Superb menu of the day, which is very well priced and uses very high quality ingredients. Lovely location to sit outside, and whilst not as busy as the main square, so very traditional and relaxing.
Not huge portions, and probably not one for younger children, but well worth it.
Perhaps have your meal here, and then walk down to the main square for a drink? You can enjoy the same atmosphere, but it is much cheaper than the "tourist prices" that you can pay in the square.
If you are staying in the Port, certainly make a point of going to both Pollensa and the old town of Alcudia in the evening. Both are beautiful, with a huge choice of restaurants and a different atmosphere to the port.