What do you need from NoPBX?
One business number going to one single user0
One business number going to multiple users0
Multiple numbers, multiple routings, multiple users0
With any size NoPBX you can also do all of the following ...
Select who of your users will be in your main ring group (not everyone needs to be)
Customize your business hours (keep your personal time private)
Customize your after-hours settings (voicemail, call forwards etc)