Toshiba, Samsung, Nortel, and Panasonic (DBS, TDA/TDE series) sold and continued to sell 30 year old technology.

The future, at this point, is with an "In House" IP-PBX and SIP Trunks.

Hosted Service may work for some, but old time multi line Key System users struggle with it and the lack of "On Site" training and support kills it.

"Reason we are going with IP Office is because our customer base isn't tailored to the new age era of hosted or other solutions."
Really?
Any sharp, professional Telecom salesperson can shoot down digital key systems all day long.
That's because your customer may not know how VOIP can improve their business and you sure didn't tell them what they are missing.

Don't think so?
How many customers have you lost to modern VOIP Technology?
(and I don't mean hosted)

Why did a customer, that you serviced for many years, buy a VOIP system from their IT Guy instead of your system?

For the same reason they have computers instead of RoloDexs and typewriters.

"While we are trying to break from the norm a bit we still have to make sure we give them something that is dependable and working well."
Well, you sure do not want to offer Avaya (IP Office).
Long time Techs here in the US and UK know where this product is going. Something about a snowball and a hill....
Just go to tek-tips.com and look over the Avaya IP Office forum.

NEC?
Don't get me started....
It is sold to alarm companies, electricians and anyone with a pulse, credit card and a box of wire.
Maybe plumbers too. You never know.
They will be your lowball price competition.

Have you ever seen an install done by either???
It is like they never heard of Punch Blocks...