I have two All Americans dating from the 50s, so I'm a bit prejudiced. One of mine I bought on Ebay and the other at a garage sale, it had a potted plant in it and had been a piece of "art" with the lid sitting next to it! I bought it for the price of the houseplant and dumped it out. Sandblasted the canner, replaced the gage and relief valve, filled it with water and pressure tested it with dry nitrogen to ensure it wouldn't blow up in my face. I have used both canners for years now and can process 51 half pint jars of smoked salmon at one time using both canners. I also have a true metal can sealer and the cans to go with it. I have also used the presto canners with no problems at all except, that every year or two you have to replace the rubber lid seal and relief plug or they won't seal properly. New seals will cost you about $15 every year or two. The All American doesn't use lid seals except for a coating of cooking oil on the surface of the mating surface, the "dogs" hold the lid in place. You should also have your pressure gage checked every year or two for safety. Many University Extension Services will do this for you for free.
Weight and stem controlled pressure cookers are safer in my opinion than relief valve units, but you have to be careful not to run the canner dry when processing for long periods (110 minutes for salmon for example) they also sound like a rattlesnake when in operation which is kind of cool until you get sick of the noise. Relied valve controlled cookers are silent but require vigilance to make sure the pressure, (i.e. temp) doesn't exceed what your shooting for.
For someone starting out I would fully recommend a cheaper Presto / Wall-mart unit, they are certainly safe, especially when new. If you find you like the hobby you can always upgrade to an All American later and save your up front costs for buying jars. Garage sales are the best place to find those, every old grandmother seems to have boxes of them for a buck a box and as long as the lip of the jar is not chipped they are reusable forever. New glass is $7-$10 a dozen.
Its really a cool thing to get into, have fun, follow the canning charts religiously and you cant fail.
Jimbo
