Millions of electric
blankets have made millions of people cozy, but still, wrapping yourself in power lines and going to sleep is an act of faith. Product defects happen, so if you buy one--buy a brand name, check for recalls from time to time, treat it gently.
You might also look for an electric
mattress pad--which goes UNDER you instead of OVER you. They have to be built stronger (you are after all rolling around on it) and they tend to use less power because, duh, heat rises and you're on the TOP of it where the heat is heading.
Cap it with a nice down comforter if you can keep it dry. Really good wool if you can afford it, or fleece i.e. Polartec which is warm but, just not the same. Wool also has the advantage if again being naturally fire resistant, without having any toxins added to it.