I upgraded to .260 a week or so ago and initially it was running OK. In the last couple of days, I started to run into random disconnect issues in the 5Ghz band. Looks like I might be giving the Merlin FW a try after all. Hate to go through all of the port forwarding set up on the router and have to set it all up again.
You don't need to reconfigure everything if switching to Asuswrt-Merlin. Only in a few cases where you might have corrupted/invalid settings stored in nvram, but try at first without wiping your settings.