I have a couple of the DeLonghi “Mica Panel” heaters, and am very happy with them. They are almost perfectly silent, and the controls are very simple, no timers or digital circuits, just a pair of knobs.
I originally purchased the second one with the intention to mount it on a wall, but the back does get very warm, and I am concerned it will adversely effect the wallpaper behind it.
One great feature found only in the user manual, you can use the heater on an enclosed porch to protect plants from frost (We had our last frost just a few weeks ago).