I've said it multiple times in this thread - you get what you pay for. The 433MHz (not Mhz) gear is non-mesh. If you don't currently have home automation I wouldn't expect someone to realize how much of a key this is to a reliable and useful system. But, go ahead - try running more than a dozen 433MHz devices on a controller - it's going to be unreliable and have restrictions based on proximity to the controller which will depend on the NinjaBlocks RF design as well of each of the individual plugs RF design. For $3, I bet it's stellar!
Even the more expensive models are half the price of the Zigbee devices!