I am not against VOIP where warranted. I started withit back in 1999 with NBX. at the time I was partners with a company called Data Technologies, who handled networks and Data Recovery.
When I first saw the user GUI I went nuts over it
Talk about sweet. We put it the Dallas office then Houston, then London then Washington. This was on a closed Sprint Network.
They were easy to sell and setup. Then 3 Com bought them out and all hell broke loose. Any SW upgrade they came up with would crash the server, no recovery, you had to wipe and reload.
Put one in a medical environment and when they started to move those huge files, more hell.
Solution? Separate cable plant. The big selling point was one cable plant.
Promised upgrades did not happen. We got out but lost a couple shirts. So when they reared up a few years later I was skeptical.

I dislike them being sold where there is no need and also the CG's blinding them with BS.
A local county school transportation district bought into this a while back. The first Guinea pig was a facility with 15 admin people in a office, a mechanic shop and a tire shop and a huge parking lot. Existing system Panasonic DBS.
We did not install but had been caring for 10 bus barns for years. We get a call to this particular one for service. Tire shop phone are not working.
Great surprise to see Cisco phone on the desks of office people. Even more surprising was to see the Panasonic phones still there. First thing I had to ask was why? The response was the computer cannot access the paging system and there was no Voice page to each ext.
The parts guy is almost always running around the parts room and he used Voice announce a lot. Guys would just call and say what they needed and he could holler back. So they used the Panny for in house comm.
I checked with the tech people at the school district headquarters (they really don't know much).
The seller told them that voice announce was an upgrade license. Also that to use the public address they would need to buy a VOIP compatible paging system or get a paging server. They opted for the server but had to wait for the next budget cycle to purchase it. $4200.00
We had a meeting with those that would listen and explain that VOIP compatible paging system was mucho BS. Paging could be connected with a trunk port for a few hundred. The selling company would not authorize a trunk port for paging. So it stayed like that till next budget and they got the server. I think there is more BS being sold to end users than Carter has Liver Pills.
The lack of buttons did not go over well either.
The shop guys were used to touching one button
with their clean finger to get who they wanted.
Also the install was joke.