I use Tomato on my AP (my old router). I eventually picked up a used Sophos device and installed Opnsense mainly to play around with it. Opnsense/pfsense definitely have a learning curve whereas Tomato was super easy to setup.
My one gripe with Tomato is, unless I missed something, upgrading your firmware is kind of a pain. You have to go out to the website, find the image for the latest version for your specific model of router, download it and then go into the UI and flash it. They even suggest wiping NVRAM which clears all your settings (I never bothered with that and it worked fine for me). It would be nice if they just had a "click here to update" button, especially since keeping your firewall/router up to date is pretty important for security.
My one gripe with Tomato is, unless I missed something, upgrading your firmware is kind of a pain. You have to go out to the website, find the image for the latest version for your specific model of router, download it and then go into the UI and flash it. They even suggest wiping NVRAM which clears all your settings (I never bothered with that and it worked fine for me). It would be nice if they just had a "click here to update" button, especially since keeping your firewall/router up to date is pretty important for security.