Don't focus so much on the features, they will tell you they have them all. Focus more on the reliability.
Windows servers.
What happens to calls when(not if) you loose an G.323. gateway or an MGCP gateway.
Is it compatiable with a third party IVR? TDM? watch them squirm on that one. When they say yes...and they will, Ask them how much the ISN cost (its a whole nother beast to get this to work)
Ask them about Call center reports How may vurses avaya? Do they have a tool to write reports like report desigener? We paid $350 an hour to have this done, because they dont have the tool.
How often do you upgrade router code now? What happens to gateways, and CCM when you change router code? (you have to upgrade it)
A good question was: "you claim to have over 8 million pages of support on your website. I'sn't that alot? I'snt most of that bug fixes? Dont you guys test this stuff before production release?"
How often does your network go down now? Do your phones go down that much now? Do you want them to? Do you always know what causes a router reboot?
How much extra does it cost to have an analog line off the CCM? (50 -100 bucks each) and not very stable.
They will tell you the audio quality is as good as TDM.. And it is for the most part on 711... ask them about audio issues for 729 over the wan. (very unstable on cisco)
ask them how many times your various windows servers have gone down for various issues.... sp2, bug fixes that broke something, viruses, memory leaks. Then contrast that as to how many times those issues happened on your TDM system.
dont forget to do a calcuation for call center outtage based on the PHONE SYSTEM BEING DOWN! I will bet you $100 bucks that in the last year your network/servers the call center agents use has gone, down but were still able to take phone calls...... NOT ON THE CISCO.... dont forget to factor in back up locaitons, costs for network redirects and such.
They will say the system is 99.999% reliablity. NOT FOR THE QUOTED PRICE! they will low ball it to make it look good against the avaya, but ask them how much more it will cost to get it to 5 9s.
most likely because your a phone guy your not going to be able to bust their balls on the network side... but keep harping on reliablity and cost.
Ask for references, and ask what the orgingal quote for the install was and what it actually came in at... and check. make sure its the same size install as yours.
dont get sold on this. you will be out the door. My last company the SERVER GUYS ended up running the phone system. NOT the phone guy (me who quit) or the network guys who wanted this.
Good Luck, and Godspeed.
RTMCKEE
CM 2.1.1
Prologix R9.05
Modular Messaging 1.1