I recently used mine when running in a new engine and can honestly say it turned a chore into a pleasure.
No more loosening glow plugs, no more jamming screwdrivers onto flywheels.
This thing is a doddle to use.
You just slip it over your engines heat sink, connect it up to any 12v power supply, let it do its thing and in less than 10 minutes your engine is up to temp and ready to rumble.
After one use I was a convert and have used mine every time I have used an IC car since.
There are two types available the 'standard' and the 'deluxe'. The main difference being that the deluxe is fitted with a thermostat to keep your engine at a constant temperature without you having to babysit.
The deluxe on the left (with temp indicator LEDs)
I have spent an awful lot of money on this hobby and can safely say that this is one of the very few purchases I have made that will actually pay for itself over the course of its life.
For that it earns a Pipski 5*star recommended rating.