I think if the cat is feral it's better to release it soon. Once the cat is a few months old it won't tame down. And if the cat is feral it will just get stressed out by being held captive. I think TNR are great, because feral cats are not pets. If caught as kittens that's different, Tibby was a feral but she was socialized at a young age. I've known a few people that have kept older ferals as pets and they hide for their entire lives. Now I know that for some cats it's normal to hide, but the people I know with ferals have claimed that they have never even seen it since they brought it home. The feral will only eat when they are not home, then the rest of the time it hides in fear. That's not a good life for a cat, while I don't agree that cats should be outdoors it's a little different with ferals.

I always keep the Strays and give thgem a home
The thing to keep in mind is that a stray is different from a feral. Strays are friendly, sometimes a little nervous or scared at first, but friendly. Ferals have never been handled by humans, they are not cats that have been abandoned by an owner.