There should be zero difference in the safety between the least and most expensive furnace. The major differences will feature related. Any modern furnace purchased in the US meets the appropriate ASTM, NFPA, et al, specifications.
More expensive furnaces will features like:
Humidifers, multi zone heating ability, economizer, multiple heat exchangers for additional burner efficiency, VFDs to vary the blower fan speed, more advanced burner ignition systems, improved filtration and some even come with electrostatic precipitators built in to help improve your IAQ (indoor air quality).
However, you will not get a "safer" furnace by purchasing a more expensive one. I guess there is one caveat - eliminating a pilot light ignition is safer as you don't have to worry about the light blowing out and having that gas leaking, but I don't think anyone is building pilot light furnaces anymore (don't quote me on that). So if there's any recommendation I can make - buy one sans pilot light.
And just like any other consumer product - a lot of times you will pay a big premium to purchase products from a marketing company which has an HVAC division... (if you catch my drift)
Make sure to get at least 3 estimates to replace that furnace from reputable mechanical contractors (not big box store resellers who just farm out work to a mechanical contractor).
The link you provided is a heater designed for motor homes. Looking at their product sheet, it seems that the power used is for the control circuitry (they have "automatic altitude adjustment" as well as a bunch of different control panel options for temperature), and for a fan - in the diagram they show hot air outlets connected through a duct system.
You didn't mention if this is for a permanent installation or not? Possibly a portable camp heater would work?
Best Answer
According to the Wiki post regarding ceramic heaters, the heating element in this type of device has a positive temperature coefficient (PTC). This means that as the device gets hotter, the power it accepts is reduced, making this a self-regulating heater.
Resistance heaters using nichrome wire or other high-resistance wire are also PTC but according to the same post, the level of temperature required is much higher.
The ceramic heater would have a greater perceived level of safety, although most of these devices have safety features for tip-over protection.
It's possible (but not researched) that ceramic heaters have a higher production cost. It's also possible that these heaters enjoy a perceived high-tech aspect, as resistance (hot-wire) heaters have been around for decades.