After near 30 years we are leaving our Axxess System and moving as much as we can, Hunt Group wise, to ShoreTel. I currently running into a thought problem in how ShoreTel thinks of Hung Groups vs. Work Groups.

I'm trying to find pointers, suggestions as we have a very large and complex Hunt Group situation (30+ hunt groups, 160+ agents across 5 sites).

The best way to think of Hunt groups would be like a conventional ring-group. It is a dialable number that you can assign members. There is some flexability on ringing but typically it would be simultaneaous.
If hunt group is busy or off hours it can route elswhere.
You can make a hunt group busy by dialing *80 + huntgroup
Work groups are more ACD orientated. You need a license for the agents to have the agent communicator. (you don't need a license to have agents be a part of the WG though)
You get additional options by way of queueing, reporting, agents logging in or out, and supervisor options.

I sent you a PM if you would like to discuss in more detail a setup design specific to your needs.

As mentioned, Workgroups act like an ACD; Users can log in or out, callers can wait in a queue with messages and on-hold music, and workgroups can even have their own voicemail box.

Both can use a schedule, but the Make hunt group busy is useful to act simular to a "Night" key (but without a button to toggle).

Workgroups can be programmed to work simular to a huntgroup. It can be set to simulatiously ring all workgroup members (up to 16).

Since workgroups reside on the server, and huntgroups are on a SG switch, it may be a good design to use huntgroups as a backup for a workgroup. If the server goes down the huntgroups will still work. If you don't have remote servers at each location, and the connection between sites is interupted, then a workgroup also won't work.

Workgroups have a higher capacity then hunt groups. While the system won't warn you, you should not have more then 16 huntgroup members in all huntgroups per switch. If you have enough switches you can assign huntgroups to various switches at each site. If you need more then 16 users per switch, then you should use workgroups.