Canners are essentially very large pressure cookers, but the added capacity makes safety even more important. The top-rated All American Pressure Canner 921 21-Quart (*Est. $220) uses a metal-to-metal seal, meaning there's no way for air to slip out or gaskets to give way. The unit also offers some backup safety features, but most owners say they've never needed them. This all-aluminum canner is extremely high quality according to owners who expect to hand it down for generations.
For canning, the capacity of this canner is ideal according to many reviewers, including the canning blogger at MyShinyKitchen.com. The All American 921 has an easy-to-read pressure gauge that's more precise than gauges on cheaper models. However, this unit is very heavy -- so heavy that most owners say they can't lift it when it's full. Due to its weight, All American does not recommend its pressure canner line for anyone with a glass or flattop range. This unit should be used almost exclusively for canning, as it's too large for most families' everyday cooking. Some owners do say they use it to cook large meals, like an 11-pound turkey, and it leaves the meat tender and moist.
If you're looking to use your cooker to can only part-time, the All American 921 may not be the most versatile option. Instead consider the highly rated Fagor Duo 8-Quart (*Est. $110) , which is roomy enough for most recipes. All American also makes a full line of pressure canners in a number of other sizes, which may be more suitable for your needs, depending on the quantity and frequency of your canning and how much space you have to store the unit.