Got the M658-G1 a few days ago at Best Buy...that sale price was just too tempting.
So far, it's a stunner, coming as I do from a 12 year-old 52" Sony Bravia (which was $3200
back in 2007).
I seem to have won the Vizio panel lottery — no mean feat, from what I've read above.
The one wrinkle was when I attached my AppleTV 4K to the HDMI 1 (ARC) port, which configured as Dolby Vision.
(Connecting to HDMI 1 just seemed to make sense to me...I only have one device, so why not connect it to port #1
Things would work for a while (10-15 minutes)...then start to go crazy....picture and sound flashing in and out randomly, and weird flashing lines and color streaks.
This would progress, until after 5 more minutes or so, things became unwatchable.
I figured it had to be the HDMI cable or the HDMI 1 port.
Switching to HDMI 2 cleared everything up.
I contacted Vizio support, and the tech support rep said that the HDMI 1 ARC port is ONLY for connecting ARC-compatible soundbars — the flickering I saw was to be be expected, as HDMI 1 doesn't have sufficient bandwidth to bring in a 4K Dolby Vision signal.
Full disclosure...I have ZERO experience with ARC devices. My receiver isn't ARC-compatible...I send TV sound to it with an optical cable.
Also...there is NO documentation or warnings in the manual...or anywhere else I could find...about ONLY connecting an ARC-compatible soundbar to HDMI 1, and NOT connecting a 4K device.
Is what the Vizio rep told me true? Or do I possibly have a bad HDMI port?