With Google Hangouts we have poor quality audio as well and at least once per day we have someone that their audio won't come thorough unless they restart their Mac.
Except in rare cases, I find the problems you're describing are usually a problem with the end-user, their equipment, or their network. Cheap phones, bad cell connection, bad voip, etc. An unmuted speakerphone with a noisy background can bring most calls to their knees.
I bought a SABRA bluetooth thingie for the room. Seems to work well.
Our results are mixed. We test out the conf room before the meeting starts. Good to go. Then weird stuff happens. People being muted. Their icon shows them talking, but no sound. People being dropped.
I don't mind the unreliability so much. 7 laws of networking and so forth.
I frikkin hate that I don't know what's broken, so can't hope to fix it. Especially DURING the frikkin meeting.