It depends almost entirely where you live. Also, if there is an actual need for opioids. In the US, both are easily obtained but there is a huge difference between the 2. If you truly have chronic pain but have become addicted to standard opioid medications, a Pain Management doctor will offer Methadone. If MRI's, etc can prove the severity of the pain, chances are take-home Methadone won't be an issue.
If there is no pain involved and it is purely recreational; here in the US, Suboxone is going to be the route they choose usually. Since a Pain doctor won't help, you will have to go to an addiction specialist. Over time they will give you Suboxone to take home but usually you must take your dose in front of them. You can choose to go to a Methadone clinic but they are not nice places and many wish to avoid it. I cannot speak for other countries, but it truly comes down to preference. If you wish to be on Methadone, you can go to a specialist who will get you into maintenance. Insurance usually is a deciding factor between the 2 options. Many people choose the Bupe as if it is purely recreational, the doses of Methadone are relatively weak.
Definitely a slippery slope and if pain is involved Methadone wins by a mile but for maintenance Suboxone truly is an awesome medication.