Garden centers are filled with good and bad watering gadgets. The important things to consider when choosing a sprinkler are:
1) How hands-on or hands-off he device is (do you need to move it frequently to avoid overwatering/underwatering areas, etc.)
2) The size of the sprinkler (is it too big/small for your yard)
3) The water output (are the streams small or large, will it over water areas, etc.)