Not a controversial guy and hardly a controversial post - and yet Senate Republicans did their utmost to delay the process. From Matt Yglesias:
Not because they had objections to him, but because they wanted unrelated policy concessions. Specifically they wanted ratification of trade agreements that the Obama administration already supported. Since President Obama had already agreed to GOP demands, it was extremely difficult for him to give in to GOP demands. Then Republicans made a new demand that the trade deals couldn't be ratified unless Congress also stopped offering Trade Adjustment Assistance funding. At that point, Bryson was being held hostage to the ratification of trade deals that were being held up by Republicans! So the post languished vacant for months. Then finally the trade deals got signed late last week. But in the intervening months Bryson had been hanging out there and so various complaints had to be made about him, and now 26 Senators have persuaded themselves that his tenure at the Commerce Department will lead to massive socialism or something.
Bryson was former president of the California Public Utilities Commission and led Edison International (parent company of Southern California Edison) from 1990 to 2008.