Voice call quality

[#1]

Does anyone else experience low call quality?
A number of people I have called have remarked that my voice sounds very clipped and metallic like. Others have reported they can hear an echo of their own voice.

[#2]

Crystal clear here.

[#3]

Very clear on mine, both incoming and outgoing.

[#4]

No - quality is indistinguishable from my previous carrier (O2).