This hobby is truly an addiction, there's no denying that!
When we pour thousands of dollars into this hobby, working to develop the reef of our dreams, there's only one controller company I can truly put my trust on and that is, GHL.
Reliability
I've been a proud owner of their ProfiLux controller since 2008 and I can easily say that NOT ONCE has the controller ever failed me or my tank. It does everything I need it to do and so much more. If you do some heavy searching for GHL ProfiLux failures, you'll be hard pressed to find hardware related issues. No controller system crashes, no random disconnects, no powerstrips randomly turning on or catching fire, etc. Take a look at the competition and it's a night and day difference in terms of reliability. Sure, the other companies may have flashier and nicer looking interfaces, but to me, none of that matters if the system doesn't work without hiccups.
Clean Design
In terms of the design of the ProfiLux, it's the most compact system I've come across. No mess of wires coming from this module and that module. That'd be a nightmare for me as I like to keep my wires nice and tidy!
With the ProfiLux, everything is connected to a single box. With others, if you want to add a second temperature probe, guess what, you need to buy a module for that and find a place to mount it! If you want to add your own float switch, yep, you'll need a module for that too! With ProfiLux, these kind of tasks are as easy as picking up the appropriate expansion card and popping it into the same ProfiLux controller box. Same footprint and more functions at your fingertips without having to worry about finding a space to mount another box, never mind hiding the wires...
The only external box I can see people needing is their Vortech Controller and LBF-AP box if they happen to own a Vortech or want to connect their Gyre or control their existing compatible LED fixture.
Expansion Capabilities
Continuing off of the same idea as above, if one manages to fill all the available expansion card slots you can always get a GHL Expansion Box 2 to add to the ProfiLux system. Doing so, will provide you with additional temp, pH, salinity, redox, 1-10v interfaces, level sensor ports, and even more expansion card slots. Although I personally haven't had the need for this add-on accessory, I can say that having such an expansive option is fantastic. Especially considering that you get so many more ports by adding another small footprint, no extra modules needed here!
Now that I think about it, their Expansion Box 2 also fits perfectly with those who have several nearby systems. Simply give each sensor a description and you'll know which system the probe belongs to.
Ease of Use
ProfiLux controllers are setup differently, in a good way.
It's a breath of fresh air when I know that I don't have to have any prior coding knowledge or even ask if my code is correct. If I need to make adjustments to my controller settings, I just use drop-down boxes and assign those commands to one of my powerbar outlets. Even with the more advanced functions, there is no need to use any coding. I just use their Programmable Logic options from the drop-down boxes and I'm good to go. If I need support, the GHL team is there to help.
Support
Coming from what their support was like years ago, it keeps getting better. The new GHL support team have proven themselves to be an invaluable resource to the company. I've had and seen questions answered directly by them on the weekends and even holidays! What company does that?!?
They're personalized approach to support is fantastic.
In addition, they've also made easy to read product manuals and launched their YouTube channel and have begun posting how-to videos for their products.
Their new ProfiLux 4
The new P4 will work the same way as the current ProfiLux 3 controllers, with the addition of new features. Unfortunately, my funds do not allow me to upgrade to the P4 just yet, but for sure I'll be getting this when I'm ready. I'm confident that the company's reputation for true reliability will continue on with this product and beyond.
***End of rant***