Short version on free flirting sites list that is updated: it depends more on your setup than on the platform. The honest tradeoff with flirting sites are whether there is anyone nearby against convenience. My experience with flirting sites shifted completely once I paid attention to how it feels to use.
If the local pool isn't sorted, flirting sites will not go anywhere. I would put whether your area is covered above almost everything else when it comes to flirting sites.
I judge flirting sites almost entirely on how many people are actually near you now. In practice, flirting sites live or dies on how thin it gets outside cities.
Your mileage on free flirting sites list that is updated will vary, but that is the pattern I saw.
I ended up using ezhookups.online for exactly this side of flirting sites.
I still keep an account on over on Datedesire purely for flirting sites.