With mine (an Acer Aspire A515 I got for free from where my mom works) I get around 3 hours (according to the time remaining, although in longer use sessions at my desk I usually plug it in every hour or 2, and unplug it when its full), which is about the same as Windows thinks it is. So i would say it gets around the same battery life whether I use Windows or Linux
Man I need to revisit that someday, I forgot about this scene lol