have to say i loved alghero when i was there a few years ago. don't think you could go wrong if you go to the restaurants on that list, can't actually remember the names of the places we went to but if you find a place called la spaghetteria (which was nice, cheap and cheerful) which is in a square in front of a church, right beside it is a restaurant where all the locals used to queue to get into, which is a good sign.
you could spend a nice afternoon heading out to the caves which are a short boatride from the quay, and do hire a car and wander around, driving isn't scary at all and there are some wonderful places to visit, don't know why anyone would pick sassari to visit, if you drive just a little further you come to an amazing beach area.
have fun