I've had a Medinilla cumingii as a container plant for about five years and I agree, they aren't difficult at all. My plant stays outside pretty much year round and has survived many cold winter nights. If we are predicted to have temperatures drop into the 40's I move the pot up against the south side of the house and throw a blanket over it and remove the blanket during the day; but if we experience consecutive nights of temp's in the 30's or lower I move my plant into an enclosed porch (and still cover it with a light blanket.)
I must admit that I'm a bad plant caretaker sometimes and my Medinilla isn't looking very spectacular right now because it's been situated amongst some shrubbery for @ 6 months and not getting enough light. I might go out today and repot it into fresh soil ... and move it to a brighter location.