Jerry has tried the M3's and it appears that so far they aren't for him. If they sound too bright, and vocals are too metallic sounding then perhaps , indeed, these speakers are not for him. I'm glad you gave them a shot, but I don't think offering you more suggestions would really help considering you're using the same electronics and room you did with the other speakers. If more time with them doesn't improve your opinion, then perhaps you should consider another speaker brand, or a different Axiom speaker. I've been following this thread with interest and I'm sorry the M3 hasn't seemed to work out for you, so far. Hopefully you'll find the solution you're looking for soon.
Epic 80 / SVS PB13 Ultra
Denon 3805 / M2200 Outlaw Monos /
Sammy 55" LED