I have no experience with Control 4, however I would recommend you stick with it. You have invested in this system, so bailing on it means losing money. Control 4 has become a stable platform from my understanding. However, as it is with any system, it will only be as good as your dealer's abilities. He should have installed a bulletproof network that is capable of handling your system. The network is the backbone of the system and therefore must be able to handle the stresses the system puts it through. There have been some software updates to C4 in the past year or so that seems to have stabilized many of the issues their dealers were having before. There are some newer processors I believe as well that I believe offer a lot of new features. You'd have to talk to a C4 dealer to get the scoop on this though.
Where are you located? There may be some C4 dealers here that can help you get your system up and running to where it should be. I am a URC dealer but hate seeing someone throw their money away thinking that the system is the issue. More often than not, it is a programming issue, network issue, or all around dealer knowledge (or lack of) issue. Posting where you are from would be my first step if I were you and then seeing who can help you from this point moving forward. I know you said the company you worked with is responsive, however if they are unable to get the system working as it should be working, then it is likely time to get someone else in there that can fix everything.