Well, look at the pros and cons:
Kitten: They’re so awfully damn cute.
The animal spends its whole life, for all intents and purposes, with you. You are the alphamale/mommy/big cheese right from the get-go. You might even get to still be the boss when the cat reaches the rarified age of, oh, two. (Though I wouldn’t count on it much.)
For the same reason, you get to work on eliminating “bad” behaviors when the cat’s still young enough for it to become habit. (No scratching the furniture, no biting the humans, that kinda thing.)
Adult Cat: Generally, the cat’s litterbox trained before you come on the scene. A big plus.
You’re doing the animal a big favor, as (sorry, no cite) for the most part, kittens get adopted a whole lot more than adults from shelters.
An adult cat, by the time you adopt it has, again generally, given up its crack/speed habit, and will refrain from tear-assing around the house at supersonic speeds. Indeed, if it ain’t mealtime, you may need to check for a pulse every so often, just for reassurance.
So, well… hell, get one o’ each. That’ll work.
[sub]Oswald… Ozzie… Hey, Oz? Fatass! Get off my foot, I can’t feel it! Great, I get pins and needles for ten minutes, and he begs for a treat. No, fool, this is gum. No you can’t have any. Remove your head from my mouth, please, you feline pain-in-the-ass.
I love my cats, really.[/sub]