You can't go wrong with either one. I, myself use a mistking. Yes they do the same thing...fine mist spray system. I guess it's really a matter of preference and budget. The starter misting is a great kit for cheap and it's perfect for chams. It sprays up to 10 nozzles. Unless you plan on having more than 10 cages, then the starter is a great system to buy.
Both are good. I have the mistking and I absolutely love it. It runs flawlesly for my 3 cages which house my 2 adults and 10 babies. It is crucial that is runs perfect as I am at work all day and it does. Here is a good Blog written by Wykd comparing the different misting systems.