I have one of the smaller single disposable tank heater buddies which has served me well over the years. It is the older design with the non-swiveling tank mount. Though these are relatively safe, I would not sleep in a confined space with one running. One issue that does come up on mine when running in a cooler environment is freeze up on the small disposable 1 pound tanks, if ran on high in a cold (near freezing temperature) space the tanks will tend to freeze up and the heater stop working when they are still 1/4 - 1/3 full, I don't know if this is an issue with the dual disposable tank models. Tanks left connected will also tend to drain down over long periods of time (weeks or months)
