Growing Strawberries and Raspberries from Seed or as Clones?

How well do strawberries grow from seed? I have heard some varieties of strawberry lose many of the characteristics of the parent plant if grown from seed. Also that the seeds should be frozen for a week prior to sowing. Are there varieties of strawberry seed that maintain most of the characteristics of the parent plant, other than the Alpine varieties of strawberry?

Same sort of questions as above, but for Raspberries. In addition are strawberries or raspberries from the supermarket sterile?