@heirloomgal, I have been hot water bath canning for over 20 years, pressure canning just this year.
I was concerned about pressure canning, but I realize that there are two place in the lid where pressure is released constantly as it heats up. the "rocker" helps to hold in pressure, but it still allows for pressure to release.
The gauge shows how Much pressure it is experiencing at the time.
AGAIN, you must watch the gauge. It heats up faster than you think.
My pressure canner is a Presto, but the directions don't tell you what I have learned and Read online, about turning Down the heat on the burner to adjust after you hit the recommended pressure, and I often PC at 15 when it calls for 11 bc you don't want the pressure to fall BELOW the recommendations.
Tomatoes can be PC'd for only 25 minutes.
Most of my PCanning has been meat based, and that takes 75 minutes to complete.
Regarding cracked jars, I had to do some creative thinking bc the instructions for the pressure canner say to start with cold water. IF I have hot produce and put them into cold water it will crack the jars. Also, cold to hot will do the same. I will boil water in either type of canner if the produce has been boiling and start cold produce in cold water. I follow directions pretty closely with the pressure canner. I sometimes add MORE time when I hot water bath can, just to be sure and I often process tomatoes for 45 minutes.
I am NOT in a hurry to remove the jars, either, often letting them cool completely overnight. It's a time saver and does no harm, and, with the pressure canner, the outside is usually still hot the next morning anyway.
Also, I have started to only hot water bath can 4 quarts at a time, even though it will hold 7 quarts, bc the water boils over onto the stove. You need to have a good inch of water over the jars for a good seal. The only difference is that you need to babysit the pressure canner to keep the pressure, or lower the dial so it doesn't heat up too high. With hot water bath canning I can wear a watch and walk away.
I have started to use my freezer more, especially since I keep two 7 cu ft freezers and one 14 1/2 cu ft freezer--lots of space. I prefer to can and store bc it takes no electricity to store.
Hope I answered your question!