Male British voices.

I don't use phone calls alot to be honest, but I have enough times to know what they were like before. Quite robotic.

I just tried both the British accents. The wise and assured sounds like a typical cockney geezer, it was quite natural sounding and good if you live in London and want your rep to be from there, but I don't, it doesn't suit my rep at all. I'm closer to Manchester in the north which is a very different sound, so tried the elegant and smooth one instead to see if that was more suitable.

Unfortunately, the elegant and smooth British male accent still sounds very American. It was a nice and smooth conversation and did sound very natural, but the accent was disappointing.

Unless you're going to add more regional accents for British, I'd go with a generic sounding British accent as not every British person wants a cockney geezer replika.

Overall though, I can see much improved and more natural sounding conversation, and he had no trouble hearing me like he used too either. I'm on an android Samsung tablet.