What's the call quality like on VoIP? Is it like a POTS call still?
I find the high quality of cell to cell phone calls very weird.
It varies based on what codec you are using. I chose the newest and highest bitrate, higher than AAISP recommend. For some bizarre reason they recommend a low-band codec over the high-band, I can only assume its because they're thinking businesses where the difference between 64k and 128k means half the call capacity.
I've never had a mobile call that was anything better than barely legible, I absolutely hate mobile calling. It was soul destroying working in directory enquiries and getting a mobile call where you had to ask them to spell out what they said because you couldn't tell what it was, and it turns out to be Pizza Hut. I actually never ended up giving them the number as they always hung up laughing hysterically at that.
I know HD Voice is a thing that SHOULD work, but I've never experienced it. Its a big reason I preferred the landline and still favour VoIP so far, although the calls are also cheaper on VoIP as I don't do enough of them to warrant a mobile contract.
Annoying thing being there are unlimited calls on my Three SIM but it doesn't support calls via the CPE Pro 2, even though the router is capable of them.