Raptive names 6,980 sites in its seller file against AdPushup’s 1,006, and 8 sites appear in both files. 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.
Both sit at a median authority of 33, so neither is meaningfully more selective than the other on that measure. Read the overlap with care. Two display networks rarely run on the same site, so most of those 8 are publishers part-way through switching, still listed by the network they are leaving. A video network listed alongside a display network is the exception — that is usually a genuine pairing.
On 5,974 more sites than AdPushup — the larger footprint of the two.
Neither has a meaningfully lower median authority, so selectivity will not decide this one.
Mostly sites mid-switch between the two, unless one is a video network that runs alongside display. The “Also uses” column on either network page lists them.