LEDE is basically an OpenWRT fork which is being actively developed. The biggest draw is that it's actively developed, and managed in a Linux-style package manager setup, rather than monolithic baked firmwares that you have to flash wholesale. Patching against things like KRACK was as simple as just invoking the package manager.

DD-WRT and Tomato are both old tried-and-true alternatives to vendor firmwares, and they require less tinkering to get into the state that you want, but they both tend to have weird crufty edge cases that never get properly fixed and don't seem to have any clear direction or leadership - they are both a hodgepodge of forks that you have to spend time digging through hundred-page forum threads to find information about. Development schedules are sporadic, and you often end up with dozens of potential builds in varying states of beta and testing which fix this or that but break this or that other thing. When they work, they're great, but my experience with LEDE has been consistently superior than my experience with DD-WRT or Tomato.