The last time I looked into OpenWRT/DD-WRT (years ago), it seemed disadvantageous to switch to them because they would be slower than stock firmware due to missing some kind of hardware support. Is this still the case these days?
EDIT: It sounds like the situation for my router (R7000) is quite the opposite now, apparently being almost twice as fast due to new hardware acceleration features.
DD-WRT is has access to some proprietary (Broadcom?) code which enables NAT acceleration on some models which, at least in my case, greatly improved performance over OpenWRT.
"DD-WRT has a license agreement and NDA in place with Broadcom that allow usage of better, proprietary, closed source wireless drivers (binary blobs) which they are not allowed to redistribute freely."
EDIT: It sounds like the situation for my router (R7000) is quite the opposite now, apparently being almost twice as fast due to new hardware acceleration features.