I'm certified on several NEC phone systems.
Recently, however, I've been put in charge of an Asterisk system with Yealink IP phones.
I have to say... pretty spiffy. I can do things with the Asterisk that I wouldn't be able to do with an NEC system (for example, play "This call may be monitored or recorded" before it even rings back)
The Yealink phones are very nice, very configurable, and have a TON of features.
Not saying that I don't like NEC, I've done some amazing stuff with them as well. I'm just saying the more I learn about Asterisk (technically, we're running a Xorcom system over FreePBX), the more potential I see in it.
A few examples:
o In a school, I could replace the "Bell" system with Asterisk, signalling class changes and stuff.
o I have 8 virtual modems for sending and receiving faxes (I could have 100 virtual modems if I wanted)
o Ring groups, "Follow Me", voicemail, text to speech, SIP trunks, T1/PRI, all there...
o A touch-screen enabled receptionist call routing system (we have two of them at the front desk)
... I'm just really liking it. Could be fantastic for "home office" stuff; put a desk phone at people's home offices.
(And yes, I know you can do some of that stuff like remote offices and voicemail and ring groups on NEC... I'm just saying I've found I can do everything that I can do on an NEC system, plus a thousand times more on Asterisk)
Just my $.02
"What the captain doesn't realize is that we've secretly replaced his Dilithium Crystals with new Folger's Crystals."
--Greg