One thing most people don't know about electric space heaters is that they all pretty much make the same amount of heat. The little desktop models make the same amount of heat as great big fancy ones.
The thing to look for is the wattage rating. Usually 1500 or 1800 watts.
Last winter we heated our 29 foot Puma TT with one electric space heater sitting on the kitchen counter. Except for the very coldest of days.
The desktop models are safer because you are less likely to knock it over.
The main differences between models is radiant heat or convective heat. Radiant heat heats the things around the heater. And you can usually recognize them by the hot glowing coils with some kind of reflector behind them. I would never use one of these. If you get it too close to something it can heat that something up too much.
The safest ones have a blower and they heat the air as it passes through and blows it out. The heated air usually can't heat anything nearby up enough to set it afire. And they usually don't have any hot spots to catch anything on fire if it falls on them.
Honeywell makes the best ones.
(I've worked for Honeywell for the last 10 years.) No, I don't make Honeywell electric heaters.