The thread's title should be changed since it's misleading.
A comparison of Trixbox and Selintra ?
Trixbox is integrating too many options before stabilizing any current version. So it doesn't survive updates, and restoring backups do not work. After running through many re-installations because upgrade didn't work I gave up. It's been the same since version 1 (aah).
Since I prefer to concentrate on one distro (SME7) I switched to Selintra. It is a major step since it is so different from FreePBX (which is really cool and intuitive). My PBX now works.
TrixBox's forum has many, many, many questions. Most of them are unanswered. On the other hand, help is widely available for FreePBX.
Selintra answers any question promptly, professionnaly and kindly. Just this leaves Trixbox far behind. I would say, very humbly, that Selintra is a compromise between direct editing of .conf file, and web-gui. Having to edit .conf file with Trixbox is a pain. With Selintra, it's very confortable.
Both systems share a common problem : keeping up with the kernel version. It has to do with hardware if I understood correctly.
But the SME7 being what it is, I prefer to depend on folks knowledgable about SME7. Trixbox (AAH) taught me how to use a PBX. Selintra let me forget about it. Selintra is evolving, but it is usable while it gets better.
The other way around is to de-trixbox the installation of a standard Trixbox and use it as Centos/Asterisk/FreePbx installation. Then you do updates manually and you personnally deal with security.