FWIW I have a t480s with the 1440p display and am using Linux and my battery life is typically around 6 hours or so for regular use. If I start running more dev tools and building things it plummets as to be expected, but the display really doesn't seem to make much difference.

The biggest thing I miss from my MacBook is being able to open it after a week of being closed and still have battery. There's definitely something not going into deep sleep when I close the lid, but that's probably my fault.