@docgreen I posted the solution for RPi3 in another thread here.
Basically because you have a technical abilities, you could get it to work reliably in your small business.
The key to the solution is to run the operating system and PBX on the SD card as a READ ONLY FILESYSTEM.
Because once the pbx is all installed and setup and running, there's no need for it to write to its SD card disk, except for once a week or so, to install system package updates etc.
The goal is to NOT let the PBX and Linux itself, wear out the SD card by constantly writing the logs, and "atime" file access times, to it.
So you run your logs in RAM in a circular buffer of 10-20 MB.
And, you have the PBX write your important voicemails onto a SEPARATE DISK DEVICE such as ANOTHER SD card attached via the USB port.
Then, you run backup script on a daily basis, to back up your voicemails and your pbx config to the cloud.
Should disaster hit and cause your pbx to fail to boot up, you just get a new 16GB SD card for your new "operating system and PBX app" disk, and restore it from cloud. Same thing for the voicemails, but with a 64GB card.
Again, the major weakness is the SD card wearing out by not putting the filesystem into read-only, not the RPi3 itself.
Also, check out benchmarks of other versions of the Pi,
http://www.cnx-software.com/2016/04...berry-pi-vs-banana-pi-vs-orange-pi-vs-odroid/