Welcome dhhavs. What exactly are you looking for first off. It sounds like you want a whole house automtation system. Something that will allow you to tie all of your major systems together (HVAC, Video, Audio, Lighting, Security, CCTV, phone, etc) but I want to make sure that is what you are looking for. If so....
There are more choices that the 4 you mentioned. All for of those systems are extremely robust, but none of them are very DIY friendly. Charmed Quark (also known as CQC) and Cinemar Mainlobby 3 are probably the most DIY frendly "profession" level automation systems out there. While they may not be completely at the same level as Crestron and AMX, they are very good and getting better everyday. (They simply have not been around as long as some of the others. Crestron wasn't as good when it started as it is today. All of these systems are evolving constantly).
Of course DIY is a double edge sword. It's great to be able to tinker with your system, but it is also extremely time consuming to set up and get it the way you want it. While most serious DIYers wouldn't trade it for the world, most will also say they understand why Crestron and AMX are so expensive - it takes a lot of knowledge and time to set these systems up.
Myself, I'm certainly in the DIY camp - personally I'm going with CQC and don't regret that decision at all.