That's a complex question.
First, they're really is no 'equal' tolerance. You can inject a half a gram or more of good dope daily for awhile, yet 2 or 3 days w/ nothing will knock your tolerance down(at least temporarily; that is how some OD's happen) not to mention the WD...
You mentioned T1/2? Duration is more relevant, yet either way it also effects things, because a potent and long lasting drug(like methadone, Which builds with repeat dosing and actually becomes more potent, with longer analgesia/primary "opioid" effects after a couple of days) is going to be hitting receptors hard, for a duration.
Fast and powerful drugs wear off fast, so they can build rapid tolerance, and quick Wd's, however reversal of tolerance can also be easier
In the end though, methadone is a weird drug, which effects people differently, and at times quite drastically, especially w/ acute use or a lower tolerance.
To me, it is comparable to Clonazepam, in that they are both highly potent and long lasting, and people generally either love em or hate em(although in fairness, the nitro benzodiazepines are more prone to paradoxical effects, I think)
People on MMT with high tolerances often have trouble getting high anyway, methadone just jacks your tolerance up and the doses are high, and many people probably l aren't used to having a potent opioid they don't have to chase.
For acute users, it is less potent, and doesn't produce much of a rush when injected, so a lot of people will not favor it.
Personally it worked for me long before maintenance. It was long lasting, and functional, and just made things better.
Though enough methadone is going to get a person "high", though, if they arlready take methadone or have an absurd tolerance, it isn' going to do much, as far as "getting kicks"