It would probably be political malpractice to offer this as an answer to the question "are you better off than you were four years ago," but the chart above (highlighting month-to-month changes in employment) gestures at what I think the most accurate response to that question is.
Barack Obama wasn't president four years ago. Nor did he become president magically on Election Day 2008. Between "four years ago" and his inauguration came the months of September, October, November, and December 2008 plus almost all of January 2009 (he took office on January 20th). That five month span was a terrible time for the American economy, seeing the net loss of over 3 million jobs. Under the circumstances, it's perfectly plausible that lots of people are worse off than they were four years ago (perhaps employed in a lower-paid, lower-status job than they used to have) but better off then they were when Obama took office (perhaps employed rather than unemployed).