I've been using Moonshiners for a year and a half, but am in the process of switching to the Captiv8 system, which is similar. The reason I'm switching is that the Captiv8 system is much easier to use. The owner of Moonshiners, Andre Mueller, is adamant that you cannot mix the Moonshine elements. This means that the elements that you dose daily have to each be done seperately. I'm currently using 8 dosing heads for my daily doses of the Moonshine elements. With Captiv8, you can mix all your elements into a cocktail each month, and only dose that each day. Captiv8 will also let you add all your "monthly catchup" elements into that cocktail. So this is far easier than manually dosing each of the monthly elements for several days after you receive your ICP results, then each of your daily elements seperately every day.
Captiv8 elements are also a lot more concentrated than Moonshine, for what it's worth.
I'm not sure about the price difference, but I suspect Captiv8 is cheaper.
They also have a different philosophy about what level each element should be in your water - Moonshine believes that certain elements should be elevated well above natural seawater levels, Captiv8 believes you should maintain natural seawater levels. But if you chose to, you could still use the Captiv8 elements to maintain elevated levels.
And the guy who runs Captiv8, Chris Wood, has a PhD in Chemistry. Andre at Moonshine does not, FWIW.
And a word about water changes. Many Moonshiners (Andre included) think you can skip water changes when on the shine. I have continued doing water changes, which you can still do. My thinking is that water changes remove more "bad stuff" than elevated nutrients, such as toxins from coral warfare. True, if you are able to maintain your nutrients at proper levels, and maintain your traces through dosing, water changes have less to accomplish. But I'm still not comfortable foregoing water changes entirely.