As I said before, I don't believe in the concept of "cat ownership" as much as cat guardianship. That said, Liz and I sometimes talk about which one of us has a closer relationship to which cat. We both tend to believe that I am closer to Arthur while Liz is closer to Beowulf. That said, we love both our cats equally; we just have a little bit closer relationship with one over the other.
I have a pretty good relationship with both boys. I really am fortunate in that I get to do all the good stuff. I feed them their wet food, I pick them up and pet them. I usually change their litter. Liz, on the other hand, has to do the harder things. She takes them to the vet, grooms them, gives them medicine, puts ointment in Arthur's eyes. These are extremely difficult and important tasks, but not always ones that the boys appreciate.
Both boys can be affectionate, though Arthur is much more people-friendly, particularly with me. As you can see in the goofy picture here, Arthur came up to me the other day (before his eye problem) and stuck his nose up to mine. I think that means something for cats, but I'm not sure what.
Beowulf is more independent. A lot of times he really wants to be picked up or played with, but it's usually on his schedule. On the other hand, sometimes Beowulf will demand to be picked up by coming up to one of us and meowing until we pick him up and carry him around.
Arthur is more laid back and Beowulf is more wild. The two of them are both very rambunctious and sometimes Arthur will surprise us by being the more aggressive one for a while, but Beowulf is usually the one getting into things we don't want him getting into. We have a theory that, even though they were born in the same litter, that Beowulf is the older brother because he tends to act like he's in charge.