Couple of questions for all M6 SL owners...

Hi all, I'm thinking of passing my M3 to the wife and buying an M6SL for myself but I have a couple of questions for all M6SL owners out there. 1. I often use the M3's onboard mic to record speeches but the M3's mic and/or circuitry puts a low-level electrical background buzz/hiss on all recorded files. It's not overbearing but can be annoying on recordings with low voice levels. Can someone tell me if the M6SL is the same or is its voice recording cleaner? If someone could compare the M3