I think it largely depends on your customer base too.
Between the companies I support there are about 2000 domains and thousands of extensions.
I would say that probably 95% of them have never heard of FusionPBX.
What I'm saying is that 95% of our customers just want to make phone calls and they have never even logged into FusionPBX, nor would they wish to.
FusionPBX is a complex beast, get to know it inside out and the flexibility and capability you have exceeds anything I have seen on the market to date.
I have tried all sort of offerings both commercial and open source. Sooner or later with commercial products I come across some 'black box' issue or other where I cannot get the PBX to do something as I have no access to the source code.
Having been involved with the project for over 10 years now, its amazing to see the progress that has been made.
Patience is the key, it will continue to rise.
Just my two cents worth