I don't hate Skype or any of its competitors for that matter, but quite a few things have to improve before I would rely on it. The annoyance of having to buy SIP connection licenses both on the Skype side and your PBX side really doesn't make sense. If your PBX is SIP compliant why not just use your PBX vendor's SIP client for voice calls and avoid that double dipping of license costs? I don't know too many people using Skype for the text chat functionality but since it has replaced Lync maybe that will change. I just see this as a somewhat clunky accessory hanging off of your PBX rather than a complete telephony solution at this point, especially if you're running one of the leading PBXs out there that do chat, video, SIP, etc.