I have spoken about this before, but I'm always happy to repeat it. It is actually my job to evaluate technology. What splits me here is should I answer this from my viewpoint as a former user, or should answer from what I feel the difficulties might be from the general home automation community in general.
Let me start at the beginning. I used QCQ for more than 5 years, but i dodn't use it now. I used Homeseer for many years before that. I left Homeseer because, at least back then, it was very unreliable. CQC was a nice change, and for the most part it was very reliable. That is the good news. The product is robust, and once running it runs, at least the operational part of CQC. The building tools are not so robust, and crashes are pretty common.
I give Dean much credit for creating CQC which is a massive undertaking. Its an environment, tools, a programming language, you name it, but it massiveness is also its weakness. Anything this massive requires massive documentation and training, and this is very light with videos the main teaching tool. I wasn't a big fan of the videos because they are too time consuming to use to look something up.
So to jump into CQC from the start is difficult. Lots to learn and lots to learn just to do basic things, and I believe this is where many just give up. I stayed with it, but there was a long learning curve, and that is just to use the GUI based system. I never made the jump to the CQC programming language. Although I have a software background from the C days, the learning curve here was just too much for me. I could have done it, but its just a matter of how much time can I give to it? Without learning this programming, I couldn't create driver or update drivers, so I was at the mercy of others, and this was the next problem, many drivers are buggy and nobody updates them.
My system used UPB and HAI/Leviton access extensively, but both of these drivers had problems. The UPB driver developer was long gone and nobody had updated it in years. Status wasn't accurate, and multiple UPB transmissions in a row would cause some to get lost. The tool to build the device file is no longer even available. I tried various queing plans, but they didn't work, and in the end, i just lived with it.
Dean wrote the HAI/Leviton interface, but that wasn't updated in years, and many newer features added to the Omni were never supported by the driver, and I wasn't savy enough to fix the code myself. Other drivers had problems as well, and nobody was fixing many of them. (This was the same with Homeseer.) I made a few tweaks to a few of them, but it was too much work just to make small tweaks.
Then there was outside access. The world is going (or has gone) web based and CQC has no good web based solution. For remote access you had to put another app on your phone, and remote PCs, and there were more new protocols to learn. Just imagine if every web site on the web required its own special browser? This is how CQC is. Everything on CQC is reinventing the wheel. More programs to load, more new programming to learn, more proprietary solutions. It just got to be too much.
Dean has since added some simple ways to get your system going, but in my opinion, that goes too much in the opposite direction. We don't need things to dumb-down things, we need documentation and support for existing technology so we can create what we want.
Finally Dean was spending much of his time (in my opinion) on GUI tweaks but my system really didn't use displays. I used LED signs and text-to-speech, lighting control, and other real-time control, and this isn't Dean's priority. I felt that in the last 3 or 4 years, very few of the CQC improvements added really helped me at all, while I lived with the most basic buggy drivers not being updated. Its clear Dean has his vision, but it doesn't match my vision, and that is the biggest problem. Vision is great, but I don't beleive Dean's vision og CQC represents most users, not mine at least.
So: 1) CQC is just too proprietary. Why reinvent the wheel. HTML and various scripting languages are redily available, and documented. Why create others that I have to learn? I just don't have the time to learn proprietary scripting and display languages, and since they are proprietary, I don't want to spend the time to learn them. In addition, Dean doesn't have the time to fully document them so users suffer, and we have.
2) Drivers need to be such that users can create them, or at the very least, maintain and fix the ones out there. In QCQ you could do that, in theory, but it was VERY difficult to jump in and write a driver, and i don't want to spend my limited time to learn a proprietary language.
3) Keep basic drivers ALWAYS updated. Dean made no secret that he liked ELK better than Leviton, so the ELK driver was updated, but the Leviton was not. Dean liked Z-Wave but not UPB, so guess what, Z-wave was updated, UPB was not. Many driver were never updated so there needs a way to get people rewarded for updating drivers that others use. If I develop a Windows or iOS or Android program, I don't have to fix the APIs and interfaces if they are buggy, Microsoft or Apple or Google does that.
Because Dean spent his time creating this giant huge proprietary programming environment, it is impossible for him to document it all, its impossible for users to learn it all, and its impossible for us and Dean to keep it all updated. There are plenty FREE open source or Microsoft or Apple supported technologies out there to build on and these need to be used as much as possible and then Dean could work just on the home automation secret sauce.
So CQC is far too complexe to learn and master at more advanced levels, its hard to maintain and fix hardware interfaces which are the lifesblood of home automation software, and at the very least, CQC needs to have an embedded web browser, and speak HTML, like the rest of the world.
If it ever goes in that direction, I might come back, but not in the current situation, not for me at least.
Finally price. For me that isn't the biggest obstacle, but I want to understand what I am getting for what price, and that is a bit foggy.
Having said all this, I know the home automation software market is challenging, and I know there are reasons Dean decided to go the way that he did, but these methods are just not compatible with my way of thinking, and just not compatible with how the world of technology is evolving.