IPO in essential mode , release 8.0.16 with one or two ATM combo is a good system for 10-20 users . IMHO, it has great price ( free 2 embedded VM channel , decent autoattendant , time schedule etc ) which we had been installed like crazy for the last 3 months. Once we train our customers to use the Call Park instead of using the old line appearance, they are quite happy with it. We've came from a 100% Norstar shop but we found it is not that hard to program the IPO , even with only the IP sets environment. ARS , SC, PRI setting is basically all ready to go right out of the box .
We've tried and honestly , quite disappointed with Partner / Norstar / Basic mode with IPO. It is quite too bare . Once customers need some more crazy call flow set up, we ran into a brick wall with this mode while essential give us much much more way to work out a solution.
