The headline is personal opinion. New Yorker publishes online (in a Feb. 27, 2017 print edition pre-release) a quite good item on Ellison/DNC, here. It is a focus piece on Ellison, but gentle in tone toward Perez; where headlining here need not be gentle, with truth trumping gentility.
To fully understand the Ellison conscience, and something that the New Yorker item briefly addressed, understand this:
That line of integrity (and campaigning enlightenment) is why people of integrity and impatience with the status quo embrace Ellison as the next DNC leader; Warren and Sanders being but two, along with pragmatists knowing "CHANGE" has to be more than a politician's slogan - e.g. Schumer and Harry Ried.
Perez, giving him some due credit, is likely brighter than Wasserman-Schultz is/was/ever will be, more like a Tim Kaine when he headed DNC, being there, moderate, ineffectual but bright and self assured. An allay of all the money and the Clinton "Third Way" disaster that put the party into tatters as Republican-lite. Less bad at that than the Clintons, probably now more careful in his emailing than Podesta; but basically Podesta-like in spirit, with a Hispanic name.
It failed. Eight Clinton years, NAFTA, all that stuff and the Podesta campaign for the second Clinton - think - either Perez and more of the same, or a broom shall be the 447 savants' decision; and with the decision making hinging upon obscurity vs reinvigoration. Ellison being the latter possibility. Ellison being a chance to capture and keep allegiance and activism of the young and suffering. Something the Democratic Party establishment has been tepid in approaching.
Ellison is sincere. That counts.
Ellison did not serve under that U.S. Attorney General who declined to put a single Wall Street crook in the slammer.
Nor did Ellison serve a cabinet position in the Obama-Biden administration, which declined to put a single Wall Street crook in the slammer.
Ellison is a core progressive. Bona fide in the Wellstone tradition.
Perez is status quo redux - with a half-hearted attempt at a veneer.