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You need to find someone who has had experience with all of them, and I doubt you'll find that person.

I have an Aquatronica. I certainly had some problems with my first unit. When it finally failed for good, it was replaced quickly under warranty. My replacement unit has worked perfectly. At the time I made the decision, the Profilux wasn't yet available.

Aquatronica has upgraded the unit firmware (bringing improvements and new capabilities) about 5 times in the 2 years I've owned it. That's a nice feature which is also shared by the Profilux.

If you intend to leave a computer connected to the controller at all times, Aquatronica has some issues that they have not yet resolved.

As for which is better....I simply don't know because I've never owned the Profilux or Aquacontroller III.