IJ doesn't act alone here. This is a stupid fucking topic that just about always ends in a flame war that causes hard feelings and makes more work for us than we care to deal with.
Since this was posted in "Off-Topic", it can only be assumed that this isn't an attempt to have a reasoned technical discussion about the merits of one engine design over another.
From a technical perspective, the 7M is the proud, final variant of the M-series of motors. It's the pinnacle of the M-Series engineering. The 1J is the first attempt to improve upon the M-Series design, but starting from a new base platform. The 2J is the refinement of everything learned from the M-series and 1J. It's longevity, lack of weaknesses found in earlier designs and overall ability to hold power proves this out.
Beyond that, it's opinion, fanyboi bullshit and emotion.
And we certainly don't need another one of those threads.