We have a couple of Polycom CX5000s too - the second one we had to source from eBay! We use Skype for Business for 100% of our voice and video communication, and have virtually no trouble with it.
Any problems in my experience stem from remote users' ISP bandwidth issues, or their inability to read instructions. No complaints about SfB.
I wonder if the author is using Skype for Business or the consumer Skype.
We're using Skype for Business and it's a daily source of issues. Call quality is often terrible and - unrelated to the audio/video aubject - screen sharing is so laggy that it is literally unusable most of the time ("Please click over there. wait for visual update "Now do..").
Another fun issue is that you cannot directly paste stuff without starting a conversation. It will block your message as "too long" most if the time, unless you write something meaningless and short first. "Hey. Skype sucks. Incoming error I need your help with:".
Video conferencing/screen share is a huge part of how my company works - and SfB is extremely reliable for us. It 'just works', if it didn't we would switch to something else immediately.
Any problems in my experience stem from remote users' ISP bandwidth issues, or their inability to read instructions. No complaints about SfB.
I wonder if the author is using Skype for Business or the consumer Skype.