Proper scheduling! That's one of the major missing pieces for all the less expensive PSAs/ticketing systems. This is about the only thing that ConnectWise does really well:
While in a ticket you can assign a status and then schedule the ticket for either
a) perform this task on this day/time (i.e: you've made arrangements with a user to do X at time Y and it should take Z time to complete)
b) follow-up with the user at this date/time for whatever purpose you deem necessary (i.e. pre-ticket closure email ensuring the issue is resolved to the client's satisfaction)
Exchange / Outlook integration a huge plus...
Also, time tracking via manual entry or start/stop.