There are no studies that compare "seeker sensitive" megachurches to small "missional" churches, but I think Dan Kimball is right to question the self-described "missional" advocate who declares that "younger people in the city will not be drawn to larger, attractional churches dominated by preaching and music."
The evidence shows that more and more people are attending large churches. Duke sociologist Mark Chaves writes, "In every denomination on which we have data, people are increasingly concentrated in the very largest churches, and this is true for small and large denominations, for conservative and liberal denominations, for growing and declining denominations. This trend began rather abruptly in the 1970s, with no sign of tapering off."
Furthermore, the 1,250 megachurches in the US in 2007 show remarkable strength across a range of indicators, according to Hartford Seminary sociologist Scott Thumma and Dave Travis's Beyond Megachurch Myths. Thumma and Travis take seriously the stereotypes of megachurches as impersonal, selfish, shallow, homogenous, individualistic and dying but they do not find the accusations match the data.
Even Baylor sociologist Rodney Stark's What Americans Really Believe lauds the strengths of megachurches as compared to small churches. "Those who belong to megachurches display as high a level of personal commitment as do those who attend small congregations" (p.48). This is significant because some of Stark's earlier work claimed growth dilutes commitment. In 2000, he declared, "Congregational size is inversely related to the average level of member commitment . . . In all instances, rates of participation decline with congregational size, and the sharpest declines occur when congregations exceed ...