Phone systems comparisons

My company is accepting quotes for phone systems. If anyone has any feedback on their experiences with different systems, it would be greatly appreciated.

We currently have a 20 year old Comdial system and have received quotes for Avaya, Cisco, Toshiba, and are waiting on a quote for Samsung.

Management interface is very important to me and ability to interface with Domino would be wonderful. Have not found any so far that interface with Domino but the Avaya system we can write a program to do so.

Please let your hatred for any products come out now with the reasons.