I have run Fresh tomato for years now but I have also run DDWRT before. The original manufacturer gave up security patches long ago for my router and many critical vulnerabilities have been found since, now unpatched on routers with vendor firmware. Tomato is kept up to date and patched and with all the recent features of a much more expensive class of router than what mine came with.

It's superior in features but it's also much more secure. Nowadays I think most should be selecting OpenWRT, it's the biggest project with the most hardware supported and if choosing hardware it's a good idea to select something on their supported list, if nothing else but to get security patches when your vendor stops, typically just a couple of years after you buy it.