I have 12 Piaf systems running, one for about 6 years now or more, I have NEVER had an issue the only time things have gone wrong is a bad internet connection or a failing hard drive.
I now use WD back drives for all systems, backup every night and have a virtual Piaf waiting to boot up if the main system goes down.
I have even played with the raspberry pi piaf - lots of fun.
Most of our systems are supporting up to 40 extensions and customers think the systems rock, so much so that people are now knocking on our door as they heard about the price point, rock solid system and amazing call quality.
I would say that the free distro is the way to go, its just my opinion but the cost for some of Smooze's plugins is exorbitant
, as people here say most of the functionality can be replicated in pIAF where you have far more features.
I usually install on wildly over spec'd hardware I never see the CPU go over 1 % for any period of time.
Learn the system, understand a bit about linux and asterisk and buy yourself some Aastra 6757i's and you won't look back.
Please support Ward here as this distro is backed by 100's of people all working in the background.
If you have a backup you can restore in a matter of 10's of minutes if not almost instantly with a suspended virtual backup system.
I looked at all the rest and this is the best it sure has some whacked features which you don't need but basically this is done right, once you go proprietary you are caught in their grasp, also if it's totally open source as this is it allows another company to easily pick up the slack if you move to another sector.