I'm also really liking the "inner bar ends" (a terrible name!) of Bike Friday's 2-piece Packalope bars. They're similar to riding on the hoods of a drop bar bike and help achieve a more aerodynamic position versus the standard position on the wide flat bars.

The bars are much wider than old school 90s era mountain bikes, which really helps with control on singletrack but are clown-car wide on the road. The inner bar ends are a great alternative hand position. I'll probably buy add-ons for all my flat bar bikes.