I purchased a pressure cooker for our boat for several reasons - less time to cook, less fuel used, less water used, and less heat/moisture escaping into the cabin when cooking. All that, and of course the safety factor of an enclosed pot, with nothing to spill - It had to be worth a try.
I resisted for several years with memories of my mother and our home "jiggle top" pressure cooker from the 70's. Modern pressure cookers are much safer.
We tend to eat veggie meals aboard. Like eryka says - pressure cookers are best for things that would take a long time to cook otherwise - beans, rice, chilli, stews, soups, etc. In the pressure cooker it takes about a 1/3 of the time compared to just boiling on the stove top (Only start the timer once it is up to pressure, just as you would only start the timer in normal cooking, once the contents is boiling) . We also make lots of soups in the pressure cooker (especially potato soup). I started off with a few recipes, but like any cooking you will soon just do your own thing and invent recipes from what supplies you have in the cupboard.
Several people have mentioned Launa Sass's books - I have her "Great Vegetarian cooking under pressure", and it really helped me get started, and also to move on and try different things once I got bored with cooking the same thing too often. Her book helped me understand the principles of pressure cooking so I can adapt any recipe to the pressure cooker.
I don't know what size you have, we have a 4 qt cooker, which has always make plenty for 2 very hungry people, often with seconds and left overs. I would not go with a smaller (than 4Qt) pressure cooker, if you then also have to limit your portions.
Mine is a cute one with no big long handle, but two small stubs (so easier to store) - I think some brands sell it as a risotto cooker. It has two settings/marks for low or high pressure settings, and inside is a max level marker so I know not to fill it too full (and risk liquid overflowing through the vent). You have LOTS of options, but mine is a Kuhn Rikon Duromatic 3042, and its 4L (4Q) - is just plenty for us. It's an expensive make, but we just shopped around until we found one on EBay for a bargain.
There are plenty of pressure cooker recipes on line too - so you don't need to spend any money on a book here. Miss Vickie's Guide to Modern Pressure Cookery
is a good all round site.
If your stove is taking a long time to get to pressure, then either you have a bad seal (purchase a new gasket), or your stove would be slow to cook anything.
If you are boiling over, you are putting in too much in the pot.
If you are burning food, (and provided you are not just cooking it for too long) then you may have a cheaper / older pressure cooker - You can resolve this in 2 ways - get a different pressure cooker with a double base and this helps spread the heat. Or purchase a Flame Tamer / Heat Diffuser (that does the same thing).
On my stove, if I use the pressure cooker, then I can't also use my frying pan, nor my biggest pot at the same time. So I plan my meals accordingly, and mostly concentrate on one-pot meals, or have whatever I'm cooking with something simple like cous-cous. If I make rice in the pressure cooker for one meal, I don't make "just enough" but make plenty so I can have left overs for egg-fried rice the next day.
I also carry a spare seal as they are difficult to find when you are out cruising.
I'm a total convert, and would not be without my pressure cooker aboard (or even if I moved back ashore now).