I use a 30,000 BTU salamander kerosene and it works great. If adjusted correctly and you use a good grade of kerosene there is almost no smell at all. I have a 25x30 uninsulated and open rafters and I get really toasty in the winter. I burn about $20.00 worth a week at $4.00 a gallon for kerosene if I am out in the garage for around 5-6 hours a day.
I live in New England and it gets pretty cold here.
On the days I am going to work in the garage I go out and let it run for about 30 min's and its ready to work in . When the temp outside is around 25-30 it stays about 60-65 in the garage. I have to shut it down every few hours because it gets too hot at times.