There both good units. The AquaRite has been around a lot longer. Pentair claims they made the IntelliChlor after looking at the strengths and weaknesses of the other brands. That's what I'd expect them to say.
I have the IntelliChlor. I chose it mainly because I have the IntelliTouch controller and I wanted everything to be the same brand. So far I am very happy with the unit.
Whatever you get, try and and get the largest cell you can so you can run the cell at a lower output and make it last longer. I have a 20,000 gal pool and I use the IC40 (40,000 gal cell). I only run the output at 40% for 5ppm chlorine. I assume if I bought the IC20 instead, I would have been running it at 80%+ for the same output.
Good Luck
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