In the past I used at work some low end routers (tp-link) in which I installed OpenWRT and worked very well.
At home I own some home routers that I'd like to install OpenWRT, but haven't found them in the supported list:
ASUS RT-N12E C1
For the RT-N12E I see that some older hardware revisions were supported, but this one has a different CPU: MT7628
For the RT-AC1200G+ I haven't found much information, neither for other alternative firmwares (tomato, merlin, ...).
The reason for changing the firmwares would be to manage VLANS easily (ASUS firmware does not allow vlan tagging for network interfaces, only for wan interface)