Frequent network drop in Nighthawk AC1900

I purchased the "NETGEAR Nighthawk AC1900 (24x8) Wi-Fi Cable Modem Router (C7000) DOCSIS 3.0 Certified for Xfinity Comcast" from Amazon. I see frequent short-disconnects on my Xfinity connection. Some info:

- I have been using the Xfinity provided modem/router for a year and never faced (as in never) connection drops

- The AC1900 is giving far *superior* download speed - but the connection drops are too frequent

- It's not a major issue when watching videos or when generally browsing. However, I frequently connect to my workstation at work and take Skype call from home. Both these are very sensitive to connection drops - and I frequently get booted out off a Skype meeting

- I already contacted Comcast who confirmed everything is good from their side. They also sent a rep home (and charged for it :)) who confirmed the same.

- Done factory resets atleast thrice, rebooted the modem many time over

- Netgear support asked me to change the MTU from 1500 to 1472 - and that made the problem even worse. So I am back to 1500 bytes

- Device has latest firmware - V1.01.23

- Issue is seen both on wired, wireless (more on wireless though)

- Issue is seen on all devices in my house

- This is the 2nd device I have tried since Black Friday. The first one was AC1600 Netgear - which also exhibited the exact same problem and I returned it. Comcast claims everything is good from their side. Their modem works as expected. My effort to say $10 a month on device cost is proving to be more expensive than I imagined.

Any suggestions?