If you are going to handicap it, Walker seems to be the favorite,
Check it out:

Wisconsin’s GOP Gov. Scott K. Walker leads Mary Burke, his presumed Democratic challenger 49 percent to 44 percent, according to a late March Human Events/Gravis poll of 988 registered Wisconsin voters.

“When looking at these data on the level of party identification, the election for governor appears to be following partisan lines with 82.5 percent of Democrats voters supporting Burke and 91.1 percent of Republican voters supporting Walker,” said Doug Kaplan, the president of Gravis Marketing, the Florida-based polling firm that conducted the poll.