Seveneves is in the top 5, but only just -- the Baroque Cycle (though not sci-fi) takes up three of the first five spots.
In terms of can't-put-down-once-started, Reamde tops the list, but, again, not sci-fi.
People seem to want to compare the content to Anathem, even suggesting it may fit into the same universe - though I can't see it myself. For what it's worth, both his SF and non-SF works are enjoyed by my other half, who usually eschews anything SF - so despite the alleged 'science-heavy style', there's one data point that suggests it's not as problematic as some reviewers expect it would be.