Heater is very energy efficient. It also heats very well. The only drawback is that is takes some time to heat up, but once heated does churn out some heat! Performance Performs great, but it does take time to warm up. Ease of Use The knob is self explanatory. You have a knob that turns on to the amount of heat you want to put out. Very easy to use. Durability This product is very durable. I have dropped it and bent the radiator part. It still works great even with the bent part. Shouldn't have bent so easy though. Design Very simple design. Its not made to look pretty, but it gets the job done. Safety This product is very safe. It doesn't get too hot, but still puts out heat. It will not ignite anything around it.