If it's so good, and the food is cooked thrice faster, why is it not always used?
Are there are disadvantages? Why to use regular pans?
Which kind of dishes are better prepared in the pressure cookers?
Well I've been a vegetarian for about 30 years and just recently discovered Pressure Cookers. I love mine.
They are hands-down the best and fastest way to cook beans, but I also use them for corn on the cob, potatoes, squash, and grains (like rice, quinoa, millet, etc). No more hours and hours of cooking!
These things are fast, safe, and generally non-burnable, unless you were to boil it dry, which I've never done. In fact there's a much greater chance of a cooking accident when you have to cook something for an hour or two in a regular pot (and then fail to remember to check it), than a Pressure Cooker, which usually only takes about 10 to 20 minutes to cook. Quinoa only takes 1 minute! (then you have to let it cool down for about 10 minutes...but really, only 1 minute!). Brown rice takes 10 minutes (plus the cool down time).
I've also tried making a Lentil Curry recipe that came with the pot and it turned out excellent.
I like to also fill my pot half full of potatoes (peel and all), put in a few cups of water, then pressure cook for 15 minutes, and they are done.
Look at the cooking times for other foods:
Corn on the Cob: 3 minutes
Beets (whole): 15 minutes
Squash (halved): 12 minutes
Lentils: 3-5 minutes
Garbanzo beans (soak first): 7-10 minutes
Pinto beans (soak first): 3-6 minutes
I never wanted a Microwave, because I don't trust the technology, but a Pressure Cooker is just as handy for speeding up the cooking of many foods.