Well, I guess I'll start.
I have a Cerebra. This was the first controller I've had, so I can't offer comparisons between one device and another; but I can offer my opinions about the device.
I currently have a pH and temperature probe hooked up to it, I plan to get a salinity probe once they're available.
This is how I have my head unit setup. Since it is so large, bulky, and sharp (?!) I keep it in the cabinet next to my tank. I have the screen timeout and sleep after a period of inactivity since it is in the cabinet and not on display. I'm hoping the'll eventually have a way to export the parameters from the unit so you can display them in a more sleek way (like a tablet or stand alone screen).
Programming was very simple. I bounced back and forth between an Apex and the Cerebra when I was considering purchasing a controller, I was trying to find a local used Apex but when that fell through and the "beta" pricing for the Cerebras was announced I jumped on board. I'm a software developer by day so I wasn't worried about programming the rules for the Apex, but it is nice to be able to simply check a few boxes in order to program an outlet.
The power bars are huge. You can see the size of them here - each of the six outlets has a corresponding LED that lights up when the outlet is in use or not. I just rewired the cabinet so things are not mounted yet, but I'm planning to have the bars mounted on the back panel of the cabinet so I can see the LEDs more clearly when I have the door open. The probes and 1-10v ports are on the left "multibar". The bar on the right is a standard power bar. Both connect to the head unit via USB. You can program "fallback" states into each outlet so if they lose connection to the had unit for any reason, they'll resort to either ON/OFF depending on what you choose.
This is my dashboard. I keep it clean, two buttons - one for clean mode which shuts off pretty much everything in the tank so I can do water changes or whatever maintenance I need to do. I have it programmed to end after 2 hours - if for whatever reason that gets pressed accidentally and I don't realize it'll kick everything back on. Thankfully none of my maintenance tasks have taken longer than that yet, I'll probably resort to unplugging it if that happens.
For each of the probe buttons, you can click and configure alerts for each of the ranges - when my temperature dips below 77 or above 80 it flashes orange. pH is the same - below 8 and above 8.5.
The temperature probe drives my two heaters, I have a rule set up to kill them once the tank reaches 79F. The temperatures are set for 80F on the heaters, so the Cerebra controls them. I plan to configure my pH probe to control my alk and calcium dosing - if it dips above or below the limits I want to kill the dosing and alert me.
This screen is a swipe down from the one above. I keep all of the plugs on a separate screen - you can click any of them to configure rules, default states or statuses. The Left MP40 is flashing because its power usage is above what I set for an alert- the motor unit is starting to make a grinding noise and the bearings will need to be replaced soon. The Cerebra is telling me that it is using more power than it should so if I wasn't able to hear it so clearly I'd know something is up.
Same goes for the heaters - if they're supposed to be on and aren't using any power or they're on and are using an abnormally large amount of power I'll get an alert.
This is the screen that shows after you click an outlet. I'm checking out my alk doser - you can see where I set up the fallback state (off if it can't connect to the head unit) - power usage alerts, and rules. There is some more set up stuff above this, like naming and a few other options I can't think of off the top of my head.
Here's the time based rules I have set up for my dosers. Every three hours (8 times a day) I dose for 2 1/2 minutes of alk. I'm running a fairly new SPS tank so my needs aren't that high yet. As my dosing demands increase I can simply increase the amount of time these windows will run for.
Setting this all up was fairly easy. If I didn't know how to write code or didn't know the first thing about setting up a controller, this would be an easy unit to learn.
My gripes? I have a few.
The design - sharp plastic corners, the head unit is huge and bulky for no real reason (the back of the unit is recessed, I'm guessing they just used the same stuff that they made the power bars out of).
Android 2.3.*. It using a really old version of Android, and the unit depends on having super user access to the operating system to work. There are a bunch of security flaws in this operating system that have since been patched, but I'm not sure if this unit will ever see an update to the OS.
The hardware running the unit is dog slow. I'm not sure what variant of CPU/GPU they're using, but it reacts very slowly. Might be the operating system, might be the very slow SD card that the OS is installed on. Many people suggest reflashing a new SD card and getting one of the fastest ones possible to make the thing feel more snappy.
The screen. They say they went with a resistive touch screen instead of a capacitive screen like our smartphones have so you can use it with wet fingers - I'm not sure I really believe that too much. Resistive screens are much cheaper because frankly they suck to use. My phone has a capacitive screen, it's waterproof, and I have no issue using it when I'm sitting in a pool.
Lack of updates on the forums. There is supposed to be an announcement about fixes coming for a lot of common issues sometime this month. I know they said it is a 'beta' program, but at times this feels like an alpha, not a beta.
Overall? I'm still happy with my decision. I hope they decide to shrink the unit down, it doesn't need to be so large. Do away with the danged sharp edges - how'd this make it out of the R&D phase? Make OS updates a priority. Put some decent hardware in the head unit so it doesn't feel like I'm using grandma's PC.
Would I recommend it? Sure. Just make sure you have room for it and a willingness to look over the occasional annoyance.
Now for the comparison.
I said this was the first controller I've owned - and that's true. I have however set up an Apex for a friend - programming is the only thing that he can't do and relied on me to do it. Anytime he makes a change (and he's a tinkerer so it happens a lot) he needs me to help write rules for him. If he had a Cerebra, he could do it himself. I've tried teaching him how to write his own rules, showing him places to get help, but as the saying goes, you can lead a horse to water but you can't make him drink.
The Apex is a lot more stable and mature. I like new tech and being on the bleeding edge, he is the opposite and wants everything to just work without hassle.
I hope that small comparison helps.
Just kidding (well about that last bit anyway 
)...but I do want to see some comparisons of different controller options! Tell us why you like yours.
