The Camco Olympian safety heaters are safer and better, IMO—available in 3,000, 6,000 and 8,000 watts, IIRC.
A bit spendy for us, at the moment. The Camco 3000 is around $200. I would like one of the larger ones for my shop area.
The Coleman BlackCat w/InstaStart 3000 BTU was $50 on eBay and (IIRC) $75 at Gander Mountain. I use them in the rooms furthest from the wood stove or in the cellar to prevent pipes freezing when it is -18 or below. So, I need multiple heaters.
My shop has very high ceilings with no ceramic chimney, meaning a long stove pipe that can draw to the point of being a fire hazard, so I don’t use wood out there on the top floor. The propane furnace is very efficient, but when/if it goes out I think I could heat up the 25’x50’ work area w/2-3000 BTU propane heaters, if necessary. Haven’t tried that yet, but I know the 1500 watt ceramics do not do the job.
For the price, Coleman makes a decent product. It is also small and easily moved around, if needed. Also, with the small 16oz propane cylinders, they take up very little room.
I was just very impressed that in 15 minutes it heated a 9’x18’ room with a high ceiling to a comfortable level, vs. an electric 1500 watt ceramic heater, which can take over an hour. With an adapter, it can fit a 20# cylinder, as well.
It is also affordable, in the short run,to stockpile the 16 oz cylinders at $5.50/ea. They last 4 hrs on high and 7 hours on low. Easier to move around than the filled larger tanks. I do have 4 of the larger tanks, but they now run about $48/each, with $18 for a refill. I use them in my business, but they are also good for cooking on a simple, relatively inexpensive corn boiler.They last about 25 hours for cooking. BTW, anyone thinking about this will want to put a metal plate over the flame of the boiler to protect their pots and spread out the heat.Keep oven gloves handy and be prepared to keep the entire cooker unit clean, as carbon soot will build up.