Very appealing Saalbach is an attractive, characterful village, with traditional-style (although mostly modern) buildings huddled together around a classic onion-domed church. Hinterglemm is less cute, with a rather featureless centre spread along a single main street. Both villages are free of through-traffic. And both are lively from mid-afternoon until the early hours. Saalbach in particular may have drunken revellers still in ski boots late in the evening.
Hinterglemm tries harder Saalbach doesn't go out of its way to sell itself to families, although it does have a ski kindergarten. Hinterglemm probably makes a better family base, with some good hotel-based nursery facilities - at the Theresia for example. And its nursery slope is better.