It's good to hear that at least some others have not had any issues :) It is certainly possible that the ISP modem may have been doing something special, but I've now been through at least 4 different routers of various grades over the years and sadly Omnia was the only one to ever exhibit that issue here. Or it may have had something to do with IPv6 or PPPoE. Hardwiring DNS to 8.8.8.8 did not help either. In the end I deemed it not worth it to waste any more time attempting to fix it.
The thing that worries me the most with the Omnia is how well it's going to be maintained.
I had no idea it used OpenWRT at all, my impression was that they made their own OS based on Linux.
So that's essentially like its own distro. Hence my worry that it's not going to be well maintained with patches for the far future.
But so far it's been great.