This is one time I don't agree with you Tech , when I hand off my routers to my children it is always on Merlin , if there is an update I phone them and walk them through the update . Never did like Auto updates , you never know what you'll get
All are making valid points here - with AsusWRT-RMerlin, there is support here, and a community behind it.
With the factory firmware, if there are issues, Asus is there to support things with their firmware, and won't be inclined to assist with third-party builds. For many users, the factory firmware is "good enough" for most folks - e.g. it's a firewall, it does the NAT thing, and it's stable and just runs for the most part.
The RMerlin builds are a significant value addition for some - and the extended capabilities that Eric offers, along with the third party community support with Entware and the scripts, this extends the platform, but to be honest, the average user likely doesn't need the added capability _unless_ they want to explore...
If I were to hand over an Asus device, I would flash it with factory, and reset it, so it's like out of the box - once they're set up and running, one can have a conversation about the RMerlin builds, and the person can make their own decisions based on the pro's and con's...