Putting together quotes to replace a 12 year old phone system and VOIP is an option, specifically Ring Central. They claim they have no hardware to install and don't even require QoS which I find hard to believe. They use Polycom phones that come with a high rating as well a Cisco option that comes with a high rating.
Question, has anyone actually witnessed a VOIP phone work without any additional hardware and call quality is excellent? My approach is if this is an option great for all parties involved. If it's too good to be true I prefer to put the right equipment in place to avoid any frustration after installation.
If you've used Ring Central even better, if you haven't but have success with another company please share.