As of 2015, Goodhousekeeping.com lists the top five slow cookers as the All-Clad 6.5 Quart Electric with Ceramic Insert 99093, Crock-Pot Smart-Set SCVC600-SS, VitaClay Chef Gourmet Rice & Slow Cooker Pro VF7900-x, Hamilton Beach 3-in-One 33134 and Crock-Pot Versaware Pro SCV1600B-SS. Crate&Barrel also gives the All-Clad model 4.2 stars.
All-Clad's slow cooker features high and low heat settings for variable amounts of time and an electronic keypad. It also keeps food warm for up to six hours after cooking is completed.
The Crock-Pot Smart-Set has a temperature probe which cooks meats to the correct temperature then changes to a simmer mode. Users can select the type of meat being cooked, and the machine does the rest. The machine has high and low heat settings, and it can switch from one setting to another during cooking.
The Vitaclay Slow Cooker Pro cooks quickly because it uses moderate pressure. After cooking, it keeps food warm for up to 20 hours. The machine only holds 2 quarts of food, so it doesn't offer the capacity of other slow cookers.
The Hamilton Beach 3-in-One has three bowls for different size dishes, with capacities of 2, 4 and 6 quarts. This machine doesn't keep food warm after cooking.
The Crock-Pot Versaware has high and low cooking settings, a keep warm feature after cooking is completed and a crock that can be heated on a stovetop. The insert is also refrigerator, oven and microwave safe.