Yes gas cook top, and I tend to thicken afterwards, I also think that most sorts of marinade are not suitable for the PC, I have a slow cooker which of course never burns but rarely use it as it has no heat control and I do not think that it produces a result as good as the PC.
My PC is a stainless steel one and is a little thin on the bottom so always have to be cautious of anything that may burn but I tend to do things in stages
Brown without top on first
Then add major items and P/Cook
After I open I continue to cook with --
Thicken later
Sweet things later
Add tender things that disintegrate in the PC due to fast cooking
IE do you want mushrooms as flavor or as mushrooms (which require hardly any cooking)
So for me the PC is part of the cooking process, I use to stir fry as a wok, then PC, then as an saucepan
