It looks very similar to one I got from Morrisons Supermarket during the winter - it was a tenner there!
It gets hot, and heats up anything nearby slightly too well. I use mine in case of emergency but prefer an oil filled or fan heater if I am in the tent. Friend of mine had on standing on a plastic floor protector and it melted slightly so I am not sure what it would do in the confines of a tent unless you have a lot of space with nothing nearby where you could place it.
------------- 'A sure cure for sea-sickness is to sit under a tree'