I've got one. It's doesn't work the way you're thinking. It's either the 1600w or 600w separately, not both at the same time, controlled by a toggle switch. I suspect it's just one element and the switch limits the power to it. You use high power when ramping up to dough-in temp and when ramping up to boil. When you reach dough-in temp, you toggle it to low power for the duration of the mash because it doesn't need all that power just to maintain a temp.
Granted it's a personal thing, but I've never felt like the power rating was a limitation, and I'm coming from a 3v propane-powered rims. It takes about 30-45 mins to reach dough-in, and that time again to reach boil after mash. I've got it wrapped in two layers of Reflectix, and I get a nice, vigorous boil. Makes great beer. If you're used to trying to evaporate your wort instantaneously, you might not like it. I've got more time than money or sense, so I like it.
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