To call methadone an opiate is kind of a misnomer. It's synthetic, for one. For two, it's used primarily in the treatment of heroin addicts (via maintenance).

From the same wiki article:

Methadone is useful in the treatment of opioid dependence. It has cross-tolerance with other opioids including heroin and morphine, offering very similar effects and a long duration of effect. Oral doses of methadone can stabilise patients by mitigating opioid withdrawal syndrome. Higher doses of methadone can block the euphoric effects of heroin, morphine, and similar drugs. As a result, properly dosed methadone patients can reduce or stop altogether their use of these substances.>

It is pretty much the miserable 3rd cousin. Absolutely no fun, with all of the same dangers that come with the usage of organic opiates. If you think it was fun, I would love to see how you feel on 15mg of oxycodone, or even 2 10/250 vics.