- Yes- a lot of propane heaters are 30k BTUs, you can get them as high at 100k. Very difficult to get that kind of heat at once with resistance electric
- When propane burns it creates water. Chemistry! You actually create over a gallon of water for every gallon of LPG burned. If thats your primary heat in a small space for a long period and no ventilation you'll get moisture buildup.
- Keroene has 50% more BTUs per gallon than propane. Not at all sure what the cost per lb is comparably. There is the smell and ventilation question, which depends on your situation.
Sidenote - I wish everything were sold by mass instead of volume.that would make things a lot more clear. I rarely care how much space a thing takes up, I want to know how much is there 
It all comes down to BTUs. How many do you need to warm up the space, how fast do you want them and what are you willing to pay for it.
