the 3do was too little too late, so would it be the M2, somewhere between 2 generations of consoles, not enough power to differentiate from the previous, and badly positioned in the time.
The 3do could not do anything against the SNES, the M2 would not have done anything against the ps1 (the DC came one year later, if you can come one year later an unreleased system, was much more powerful, has great games and floped badly). There is a lot of reasons Matsushita canned the M2 without even trying.
By the way, I'm one of the 5 owners of a 3do system in the world
So I know about the M2