ok to compare apples to apples (or green apples to red apples actually)
Partner R7.0
8 6 button phones
1 18 button phone
NPL : $2809
IP Office 406 v2
8 vcm channels
2 expansion cards for 8 analog lines
8 5602 phones and power cords
1 5620 phone with power cord
mounting bracket and power cord
NPL: $6755.40
Big difference in price. Labor and cabling would change the costs some which would bring the prices a little closer together.
Also given the configuration, the IP office has more features for the money.
The Partner is only capable of 5 lines, 9 analog/digital extensions plus MOH capabilities. To add any other auxillary equipment would incur additional costs.
The IP office is capable of 8 lines, 8 digital extensions, 2 analog extensions and/or paging, "several" IP phones, 8 port layer 2 switch, MOH, and basic voicemail(available computer required)
If the user of the above Partner wanted to add more phones, they would have to not only purchase additional phones but also purchase a carrier and new module.
If the user of the above IP Office wanted to add more phones, all they would need is a new phone with power supply.
Not a fair comparison at all for a small office. IP phones and the IP Office in general isn't justified until you get over around 20-30+ phones.