Well, being a werewolf would only happen every 28 days or so...

you also have to consider what version of werewolf? twilight? True Blood? traditional? etc

Twilight werewolf. Control over turning. Though you imprint like ducks uncontrollably onto lovers[or babies]and get really sick when that person dies.
But you also get a tan. And land that's all to yourself that the white man can't do shiz on.

Being a werecow would be safer. When you turn into a wolf you go crazy and try to kill your loved ones. But if you turn into a cow, you'd just be like "Moo... feed me."

is this a decision between two positive things? xD who doesn't love sneezing? who wouldn't wanna be a werewolf?

WHY MAKE ME CHOOSE?! THIS IS EVIL!

Having this happen to everyone on Earth instead of just me would actually make it somewhat safer for everyone. We'd all turn into werewolves at the same time (assuming it's the standard full-moon thing) so nobody would get hunted by werewolves, and since it happens to everyone else too _I_ wouldn't be hunted by _non-_werewolves. If it's not the random rampage type and we keep some semblance of our wits about us it could even make for an interesting sort of monthly holiday.