I bought a mojo not long after they were released, but sold it after some time as it wasn't getting used much. See my avatar for how hot it gets when charging
Back then I had a lot of issues with emi - mostly GSM buzz. I would get the noise whether it was connected to my pc or my phone, but this was likely because my phone was always nearby.
A few weeks ago I bought a new mojo and I haven't had any issues with emi. Probably because 4G doesn't interfere as much as GSM.
I know that the mojo didn't measure very well on ASR, but subjectively I don't have any complaints about the sound - Particularly now that I don't have any noise issues.
I've attached a PCB photo from mine, if anybody is interested. The PCB revision is from 22/03/2017.