Here are some of things to consider
1. What is maximum number of extensions it can handle WITHOUT having to replace "PBX on wall"?
Check capacity on system you are purchasing
Do you need a larger system in range to get maximum capacity stated?
Find out at what stage you will need to invest in a bigger box
Get this information in writing!!!
2. How will it help our customers communicate more easily with us?
DIRECT DIALS allow calls to by pass switchboard
VOICEMAIL takes messages if you cannot get to phone
Access to messages can be remotely as well as from your handset
3. How can it improve our Customer Relationship Management?
CALL LOGGING itemises missed and answered calls
Return missed calls to improve CRM
4. How can mobile staff work effectively?
DECT allows you to contact people wherever they are in office
It can be used to locate people who are on another site
HOT DESKING allows people to log on to any handset
Unified Messaging stores emails, fax, SMS and voice in one location