I love animals but have always favored dogs over cats. That changed when a hungry stray black & white showed up one day and we've had her for 6 years now. She'll likely go down as my most favorite pet. She's a dog trapped in a cat's body, comes when called, likes to play, constantly entertains, is quite a talker and can charm anybody. I've done some casual research and it seems black & whites are known for their calm demeanor. This cat of mine will curl up and snooze while there are 20 people walking right past her at a party. She'd be a great store cat. Oh, and she lives outside mainly and she prefers it that way. No cat pee smells or clawing damage in my house! I've gotta draw the line somewhere.
My suggestion is to check out the animal shelter. It's much easier to gauge the behaviors of a mature cat and see how you both interact with each other.