When doing my PPL training in one of the 'simulated instrument' hours we were just under the cloudbase when the pretty white crystals came floating down.
My very experienced instructor told me to take the goggles off, count quickly to ten to enjoy an unusual spectacle, then fly a 180 and get the h@ll out of it. I guess that why he's an old pilot.
Regardless of having an IMC or even an IR, an iced airframe is about as much use as a brick.