Compared

Prices change. Every claim below carries the date it was read and a link to where it was read, and the build fails if either is missing — an undated claim about someone else's product does not stay neutral, it asserts “true now” forever.

The gap

None of them publishes a fill rate, a rejection rate, or any measure of how often a surfaced line is still available when you tap it. That absence is what Bookbreaker is built into: a screen sorted by raw expected value is sorted partly by how stale its own data is, because the biggest numbers cluster on the books that moved most recently — which are the books most likely to have moved again.