I think this is what I love most about cats ... their personalities are so unique.
Our vet has told me several times that there is a window of opportunity for socialization of a kitten. Once that window is closed they are unlikely to be socialized. I have reservations about that because I once took in an 8 year old feral and no on thought I could socialize him. He turned into a very shy but loving cat.
As I type, there is a big red, 20 pounds, part-Persian kitty sitting on the table beside me purring. Every once in a while he will reach down and nip my hand. We rescued him 2-1/2 years ago. They told us at the HS that he had been very withdrawn since he was brought in ... when he saw my husband he sat up like a prairie dog ... as if to say look at me and please take me home. He has a fabulous personality but was apparently hit by a former owner. It has taken him 2-1/2 years to settle in and realize that he is never going to be hit again.
My most recent feral is a real sweetheart. She is ready to come over to the house now. I am eager to see how the others will take to her. She will first be in the mudroom ... and the others can get acquainted with the fact there is a new cat by sniffing under a closed door. Wish me luck.
My vet has about seven cats who live in her office. One of them was a pregnant momma when she was rescued from an alley with all the other ferals. She had her kitties at the vet's, and they kept her because she was so great. She ALWAYS lays on the keyboard at the front desk. She's a very sweet girl.
Good luck with your new one. I love having new kitties.