It's a great product to work with. I have been using it in my environment, and if you use it, you have to say that VoIP can't get any simpler then this. It's for the layman use and it also comes with a free version(though this version has a few restriction). Also unlike other types of VoIP software, 3CX connects to public telephone network through independent or hosted SIP gateways.
Room for Improvement:
It is not supported by Linux versions. One using this software has to stick to Windows, Which can be a bit of a thing of concern for a some Administrators. For Linux, one has to switch back to other products. This product is also not open source, which is not much appreciated by the guys like me, who love experimenting with the codes of any product they receive.
Disclosure: I am a real user, and this review is based on my own experience and opinions.
Dec 20 2012