My personal opinion would be to go cold turkey, or make sure your supply is somehow limitted so you only ween as long as you need to and you actually stretch your supply out.
I don't believe anyone should go through withdrawals so severe they're throwing up violently, but ultimately you have to face the fact that reguardless of how you quit, most likely you're going to feel like shit for a week or two and you have to take it. If you ween, it just prolongs the negative feels.. they're not as bad but you're talking about an extra week or two of feeling bad instead of just taking it all at once like a man.
And no, I know firsthand that making yourself go through that isn't going to keep you from doing it again, but it WILL teach you good discipline and willpower. Most likely you will start using again, and the more discipline and willpower you have, the more control you'll have on your addiction and if you can't get rid of it, at least you'll have a better chance of being able to keep your life straight and function normally despite your addiction.
My other thought is that if you really make your mind set that you're going to stop and you just can't manage to do it on your own, definantly go see a doctor and be brutally honest. The duration of your use, the doses and the details of your withdrawal when you try to quit are crucial. The doctor is there to help you and at least if he/she is in the United States, that's all they are going to do. You don't get reported to the police or anything like that for admitting drug use or even trying to seek treatment for addiction. Infact, voluntarily seeking treatment for addiction is pretty much the only way to be a respectable druggy in this country.
"Oh look at me, I'm going to meetings!" and everyone will pat your back and applaude you for it like you really did something special when really you're just compensating for the fact that you're a fuck up.