Mediavine names 8,643 sites in its seller file against Ezoic’s 8,490, and 35 publishers run both on the same pages. Reach is only half the question though — the authority spread below shows what kind of sites each one actually carries, which is what determines whether you would be accepted and what the inventory is worth.
Mediavine is the more selective of the two, with a median authority of 29 against 7. The overlap figure is the practical one for a publisher: 35 sites already treat these two as compatible rather than mutually exclusive.
On 153 more sites than Ezoic — the larger footprint of the two.
Median authority of 7 against 29 — more of its sites are still small, so a growing site clears its bar sooner.
They treat the two as compatible, not either/or. The “Also uses” column on either network page lists them.