But the most annoying problem with any internet voice chat is not so much the quality but the latency. Landline phones have noticeably lower voice quality but one can still enjoy a conversation perfectly well. High latency, on the other hand, absolutely ruins the experience.
I always see these services talking about "crystal clear quality", but never latency, which is a shame. Maybe there is simply nothing they can do about it. I've noticed latency get worse and worse on the Internet since I started using it in the 90s and nobody seems to talk about it.
There are so many more sources of latency on every layer on the modern internet and it's a damn shame. I remember when interleaving got enabled on my ADSL and latency to everything doubled overnight. Then there are NATs, and all kinds of filtering shit that ISPs insist on. Sigh...