Politico's Glenn Thrush:

Conservatives are right to trumpet the Brown-Coakley race as a referendum on health care reform -- but it turned out to be a referendum with no decisive victor on the defining issue, according to a postgame analysis by pollster Scott Rasmussen.

... versus Politico's David Catanese:

Scott Brown's opposition to congressional health care legislation was the most important issue that fueled his U.S. Senate victory in Massachusetts, according to exit poll data collected following the Tuesday special election.

One possible reason for the disagreement? The exit poll Catanese relied on was conducted by Republican pollster Tony Fabrizio, though Catanese doesn't tell readers who commissioned the poll.