I really like this phone and we've bought about seven so far. Our hybrid PBX does not work well with it though so I would stay away if you are connecting to a Toshiba Strata CIX.

So far I love this phone, after updating configuration I am just blown away with the possibilities. I am currently using my Steel Series Siberia 840 to vvx 500 which is connected via usb to the steel transmitter. I also tried logitech H390 headset and it worked decent. Also if you have a headset thats not usb friendly you can use a USB sound card dongle which has the 3.5 or 2.5 jacks for mic and audio then the phone will recongize its a headset outlet. Polycom states that plantronics, senheiser & Jabra are the only compatiable headsets which is not true. Other headsets will work/ function but some features might not work for example the wireless volume button on the headset or mic level options. Anyways hope this info is useful. :)

Client loves the touchscreen. This phone is top notch.

I got a refurbished model for cheap and just set it up for Skype for Business PSTN. I have a VVX600 in the office and didn't want to spend quite as much for the desk phone in the home office, so this came in handy.
I reviewed the VVX600 already, and nearly everything I said there is true for the 500 as well. Configuration is cumbersome if you don't have a provisioning server, and the learning curve is steep.The fact that I cannot reuse the headsets (RJ9 vs 3.5mm) is astounding, especially since adapter cables cost more than what I paid for the my current headset that I can use on the computer as well, but not on the VVX.

The difference between the 600 and this is
- fewer lines (irrelevant in Lync mode because there is only one line).
- smaller display (4 icons across instead of 5, 2 columns of contacts instead of 3)
- no Bluetooth

That's it. Once I had it reset to factory defaults, changed the baseline config to Lync, and let it do its thing for a while, I was in business. It upgraded itself to firmware 5.4.1.17653.
My calendar and contacts synced down fine. The color display and touch screen are nice, but the phone is just as laggy as the 600. You have to dial slowly. Kind of crazy for a phone at this day and age. The Cisco phones are sooooo much smoother (I have an SPA514G sitting right next to it) and better as phones, but just not as flashy. And they don't work with Office 365.

Bought these instead of getting them from our phone provider for the business. Work great.