Daily grooming is essential, if you choose a long-hair and want to keep him healthy, good looking and free of hairballs. A short haired cat requires less maintance, just gentle brushing with a rubber brush, a couple of times a week. Unless cat breeding is your goal, sex makes little difference since you're going to spay or neuter the cat anyway. Altered pets are more docile than whole cats. Neutered males normally never spray and are more mellow because their not driven by hormones.
Males are always larger than females.
Spayed females won't produce generation after generation of unwanted litters at home or elsewhere.