I have a TP-Link Archer C7, and while it has generally been pretty good, the last six months or so it will simply drop all connectivity and require a reboot. Pretty frustrating (happens 2-3x/week) and has me looking for another replacement. This is with stock firmware though, so I would hope, but haven't tried, that alternative firmwares would fare better.
I've had the same issue happen, running Archer C7 running OpenWRT. But I'm not 100% sure it's actually the router or whether it's really a problem with my ISP. I haven't seen the issue in a couple of months now, yet I've made no changes to my setup.
I did have considerable issues getting both wifi interfaces to work well at the same time, but that's probably more due to my own incompetence more than anything. I did finally manage to make it work, much like how you'd wiggle antennae on an old tv back in the day and suddenly you got a signal.
Why not just try flashing OpenWRT? I've been using the Archer C5 with OpenWRT for over a year and everything has been working flawlessly. Setup is incredibly easy as well.
In my experience the alternative firmwares were worse.
I ended up contacting TP-Link support and they were actually quite helpful though. They sent me a beta firmware that's mostly resolved the issues. I don't know if it's been publicly released yet though (I got it around a year ago now from memory).
