It will be next to impossible to get unbiased information on this topic. People defend their controller choice as much as their salt choice...
I have used Apex for 7-8 years now. Never had a single piece fail on me so far...knock on wood. What is Apex good at? Just about everything. They have a few duds though. The EB832 is extremely overpriced and underbuilt. The Trident has way more problems than people care to admit and the ATK doesn't seem to be reliable enough IMO. The new Tasks feature helps a lot with programming. Learning to "code" with Apex can take a minute.
What is Apex really bad at? Making anything remotely water resistant. I know, it is odd to expect a manufacturer in our hobby to think about water being around their products but Neptune doesn't even think twice about it. Look no further than the SKY for proof here...
I have been running Hydros for 6+ months, I think. Major connection problems out of the gate and I am not sure they have ever been solved. I just changed the warnings to not alert me when the power bars "disconnect". CoralVue tried but they were zero help in fixing this. In the end, I was told it was an issue on my end and good luck. This is where Hydros is going to fall flat if CoralVue doesn't have a change of attitude. CV will run people away from Hydros with their attitude and lack of customer service. Which is sad and gets to my next point...
What does Hydros do well? Almost everything. Easier to setup than Netpune by a long shot, easier to update, better build quality, connectors and modules ACTUALLY designed to be arond water, and much more open to work with 3rd party so far. They are also introducing new items almost monthly it seems.
GHL? I used the Mitras lights for 4-6 months and I will never give GHL another dollar. Easily the worst software in the industry and very little help. Setting up a phone call during my work hours isn't going to cut it when there is clearly something wrong. I know my way around computer and networks pretty well. GHL is just terrible on so many levels.
But what does GHL do well? They have the best hardware in the game. The Mitras light was incredibly well built and worked like a charm once I got it working after 4 hours and pure luck. Still, I sold it off and said good riddance. I can get a good light from half a dozen companies these days. If their software is that user unfriendly, no way I trust my tank to their controller.