GARDEL  I tried this out as a result of the MacZot offer (40% off) and was sorely disappointed.

First of all, the product severely favors Sip Phone (aka: Gizmo Project) and something called CallCentric. Unless you are on one of these providers, trying to get this to work is a nightmare. There are hundreds of great SIP providers out there, why limit it to these two? Is the author gettting paid by them? Isn't this something we should know.

Second, for some reason, this thing is written in such a way that the Mac Address Book hijacks the dialer when trying to do extension dialing on a PBX. The softphone registers fine with the ipen source asterisk PBX, but if I try to dial someone on the same PBX with a 4 digit extension, the softphone tries to find a match in the address book and won't let me dial the extension. In other words, I can cal outside the office, but not within it. Very poorly thought out. This was enough for me to dump it.

Third, in an effort to make it look like an iPhone, this product is cumbersome and counter-intuitive. The icons are small and not representative of what they do. There are way too many buttons on the phone, many of them unnecessary.

Finally, even at $21 (the MacZot price) this softphone seems overpriced, at the $35 regular price it's a robbery. Many better options out there. This one was clearly put together by someone with little clear idea of what the power of SIP and open platforms is about.  
(Version 2.0045)