Using VS2015 Update 1 along with WebEssentials downloaded just today. The recording button is not available in the IDE and the unused CSS option is not displayed on the webbar. In addition I actually can only get the webbar to display in Chrome(Version 48.0.2564.109 m). It does not work in not IE (11.0.9600.18163) at all.
Would love to hear back from you guys, really wanting to use this tool, and have about three hours invested in trying to get it to work.