These are a good choice
The smell is really not much of an issue. They do not take electricity unless you run the fan and they have very few moving parts to fail. They are quiet and relatively cheap. You can get parts to fix them which do not cost a fortune and it doesn't take a rocket scientist to fix. My friend had one bigger than this one for a 46 footer and it worked ok for him. He did have some trouble with the fuel pumps but they ran all of the time because he lived aboard. For a 38 footer, you could use a day tank too and not have that worry. Otherwise just carry a spare pump and the tools to swap it out. Plan on that when you install the thing and you will have a much better, happier life.Down side is that they do take up room in the cabin and you probably will want a fan to move the hot air around.The Espar style is small, expensive, complicated, noisy and uses up the batteries. It puts out very nice hot air wherever you put an air duct.There is also a propane model which is very, very slick but requires that other fuel and that may be an added number of complications.Fred has pointed out some of the limitations but they are not all that bad if you install them properly. See the link for Fred at work!