We use Dolibarr for customer relations and to help with stock distribution, see here: https://www.dolibarr.org/
The Nethserver here is for administration of the business, as an email server and to store vendor files, firmware updates, logs, etc.
The setup here is: Internet--------WAN [Nethserver] LAN------switch--------Desktops (Mint 17.3 and Windows versions).
The install was made using a downloaded ISO and we followed the online documents, added the users and then connected it all up. It worked first time, no problems. After a few days, we then added ownCloud using the Software Center, and about a week later installed Dolibarr.
No users knew we were doing these additions, and there were no complaints - we never took it offline.
I can give feedback on our own Nethserver installation and performance, but based on the last month using it ‘live’ we intend to deploy more Nethservers at our customer locations soon.