I'm currently on methadone, have been since around October. I started tapering just over a month ago and I just got under 50mg, so I'm half way there. It's going to be a much slower process from here on out, you can make bigger drops initially then you have to slow down. But I'll be off by August, which is when I turn 21 and MediCal kicks me off so it's good timing. I could probably taper faster but methadone is really stabilized me and given me a lot of security and peace in my life which I know I wouldn't have gotten from bupe. However, I started methadone after 2 years of opiate abuse, the last 3-4 months spent binging on IV heroin.. due to tolerance, my habit was really big and I'm still paying off the debt I racked up to this day.
I think bupe works wonderful for smaller habits or if you're coming off less potent opiates. But for IV habits and really potent opiates/opioids I really think methadone is the way to go. I agree 100% with the person who said you have to be careful not to up up up your dose trying to chase that high. Tolerance sets in quick and while the methadone will keep you comfortable and craving free, the initial high will fade away quickly and all increasing your dose will achieve is making tapering a really lengthy, pain in the ass if a process.
That being said, it's all about finding the right dose! Too low of a dose will not "hold" you and you will not be comfortable and/or have cravings. Also, coming off an IV habit I really needed to get up to 80mg because for me that was a blocking dose.. once I reached it all other opiates were ineffective. Before picking up the needle, I probably could have started at 40mg and stayed there as I'd always been in control of my habit and physically dependency and a two jobs kept me using. But IV was a whole new monster.. and it really took not being able to use for a few months to really stabilize me before I was able to start my taper.
Not that there are no cons to methadone... you have to know your shit and you can't let yourself get complacent. Some people just go up and up on their dose and stay on methadone for years and years. Those people have a really hard time getting off and sometimes never get off. Keep your dose as low as you can, work on the issues that led you to use, and start your taper. Doesn't matter how slow you taper as long as you're tapering.. whatever works for you. The most common side effects of methadone are sleepiness, sugar cravings, sweating, and constipation. Side effects are more pronounced with high doses. Now that I'm below 50mg I have almost no side effects. But even close to 100mg I managed the sugar cravings by eating fruit which also cured the constipation. I do sometimes get really hot so at my house the windows are always open and I don't wear a lot of clothing.

A lot of people pushed me to do bupe but I know many people who went that route and sometimes it just isn't enough.. and going into the methadone clinic isn't that bad, I like the routine and I got my take homes really quickly. I heard all this stigma and stereotypes regarding methadone so I thought it was going to be this awful thing but I really have no complaints. I wish more people recognized what a life saving medication it can be.
I've heard great things about bupe being used off label as an anti-depressant. But methadone is also a proven mood stabilizer. I've dealt with depression as long as I can remember and during some periods of my life I couldn't even get out of bed. Opiates have been the only thing that have worked, without them I literally can't function. Work, school, and just leaving the house are impossible without them. I learned pretty recently that it's very likely that I was born with an endorphin deficiency like my dad. Methadone is very effective for my depression.