The only parts of OpenCRM we don't use is the Invoicing (only because we have a long standing supplier of accounting software and did not want to change anything here) and Helpdesk.
This is how we use OpenCRM:
Asset management (ie. customer equipment serial number, access codes, location, model numbers, service history, service contracts applicable)
Preventative Maintenance Service Activity (including synch to Outlook and service engineer mobile device)
Breakdown Service Activity
Jotform integration (for electronic service job sheets and automatic linking to and completing maintenance visits automatically)
Campaigns (lists and activities)
Events (to do lists and storing records)
Automatic Breakdown Counter
Synch calendar items to Outlook and mobile devices.
Storing service records
Activities (eg. meetings, calls etc)
Extensive reporting (highly customisable reporting allows us to search on all parts of our business activity including things like service visits not completed, contracts due, warranty due etc etc)
Review collected by and hosted on G2.com.