I'm a flatlander, not much elevation here, but love to cook in them cuts the time down so much. Using a Fagor no problems, but have used an old one with the ratteling weight on top, liked that because, if it was rattling too fast, knew to turn down the burner.
Did learn not to put green chili sauce in with meat, burned to the bottom of the pan (woops) but cleaned upwell, now add after the meat is cooked, to still get the flavor. real chili might work better with less chance of scorch.
Have been warned that they can go boom, if in a hurry to open have let the steam out first, propped spoon on the weighted ones just to lift a little. the other has a release on the handle, psstpsst :)