I heated my old shop with Kerosene/Diesel everyday. Cost me 20 a day to do it but it worked very well.
I ran Diesel must of the time because it actually seemed to burn hotter. And to top it off, it seemed like it burned cleaner.
Either way go with Forced Air, it will do the best for you which ever route you take.
When it comes to clean burn I myself having the option would use Propane. You can go to TSC and buy a 40lbs Tank, versus the 20lbs that you use for grills. And if you have a Flying J, or a Propane fill station near you, its a hell of a lot cheaper to refill then exchange.
For example when I refill my tank for the grill it cost me $9.00 vs. $20.00 to exchange.